The development of lanterns continued through the 1930s and accelerated when it was determined that the lamp’s brightness and its long length made it less susceptible to glare. Lanterns with bare bulbs suspended over an overhead reflector (the so-called "seagull" lanterns) quickly followed. Glass manufacturers were initially slow as the first plate refractors for low pressure sodium lamps didn’t appear until the end of the decade.

The advantages and disadvantages of low pressure sodium were readily debated, especially when an alternative (the medium and high pressure mercury discharge lamp) was also available. The monochromatic light was considered especially useful for arterial and traffic routes, the lamp’s shape cast a wide beam across the road surface, the light was also considered more penetrating in foggy conditions and it was the most efficient light source being manufactured. However, the light was also considered inappropriate for high streets, promenades, civic areas and residential streets and so some lighting engineers restricted its use to traffic routes only. Therefore low pressure sodium became known as "the drivers’ lamp."

The arrival of plate glass refractors resulted in large lanterns made of metal frames enclosing heavy glass sheets. These bulky lanterns continued to be made into the 1950s until being usurped by lanterns with plastic bowls and machined or moulded plastic refractor plates. The lanterns were still large; the size dictated by the bulky control gear, but their design and construction was becoming simpler.

The 1950s and 1960s saw huge improvements in the construction and efficacy of low pressure sodium. Early two-piece designs (dubbed SO) were replaced by the one-piece, more efficient integral design (called the SOI). The development of linear sodium (SLI) broke the one hundred lumens per watt barrier, lead to a radical rewriting of the British Standards of street lighting and prompted the development of new families of streamlined lanterns. But it wasn’t until the arrival of a new heat-reflecting technology (called SOX) that a cheap family of extremely efficient bulbs became available.

The energy crisis of the 1970s saw a rethink in street lighting and lamp efficiency became dominant when fuel was both in short supply and expensive. This saw the large scale removal of colour corrected high pressure mercury, fluorescent and ancient tungsten lamps by low pressure sodium replacements. The old arguments that the smoky-orange lamps were inappropriate for residential areas no longer applied. By the end of the 1980s, low pressure sodium was the dominant street lighting lamp used in the UK.

The use of low pressure sodium came under scrutiny again. High pressure sodium, finally developed as a viable technology in the 1960s, was coming of age and offered a compromise of slightly less efficacy with better colour rendering. Questions were being asked about the physiology of the eye and visual adaptation under low lighting levels; previously the wavelength of low pressure sodium had been deemed the most suitable, but research now suggested that the eye responded better to white light. Concerns were raised about light pollution and the low pressure sodium lamp was seen to be the chief culprit (although it was more to do with older non-cutoff and semi-cutoff optical designs rather than the lamp itself).

By the turn of the century, the age of low pressure sodium was seen as coming to an end. Research in white light technologies, especially metal halide and a renewed interest in compact fluorescent coupled with the advantages of using white light at low lighting levels, saw the end of the low pressure sodium lamp’s dominance. Its use was discouraged in the specifications, lantern manufacturers started to wind down their production and bulb manufacturers followed suit.

By the end of the first decade of the 2000s, low pressure sodium was in stark decline, and less and less of the UK’s streets were being lit by its characteristic orange glow.

Name: Philips MA 90 (MA90 090XDS00*1)
Date: Mid 1970s - Mid 2010s
Dimensions: 819mm, Width: 270mm, Height: 180mm
Light Distibution: Semi Cut-Off and Cut-Off (BS 1788:1964, BS 4533:1976)
Lamp: 90W SOX

The 1970s saw increased competition amongst the UK's main road street lighting as companies vied to tender for the lucrative new motorway contracts. The main players, the GEC, Thorn and ELECO, all pushed their lanterns, and made claims for their luminaries to be the 'first' or to have been used for the 'largest' contracts on a new motorway scheme. Another player entered the arena when Philips joined the fray. The Dutch company had been instrumental in the introduction and sale of Low Pressure Sodium (LPS) lamps since the 1930s. However, the firm never produced UK specific luminaries, preferring to pair up with other manufacturers for advertising, marketing and sales. This led to some UK manufactured lanterns being rebadged as Philips products – the main road lighting GoldenRay lighting range from ELECO being a well-known example, as it was sold by Philips as the MA 5, MA 6 and MA 9. This changed in the early 1970s with Philips introducing the MO5 "Links" Lantern, a design specifically catered for the major motorway construction at the time. Spurred on by its success, the firm decided to fully enter the UK market for itself, designing luminaires which would meet British and European Standards, but which would have several new features. The Links lantern was joined by the MO62 "Catenery" Lantern, and the firm started boasting their own 'firsts' in multiple-page glossy advertising features. Seeing further opportunities with the expansion of the UK's motorway network, and the re-lighting programs spurred on by the energy crisis, Philips embarked on an even bigger venture, and designed a new range of LPS and HPS lanterns for the UK market. Noting that competition was fierce, particularly with the established players, Philips knew that their new main road LPS luminaries would have to stand out from the crowd. Starting with existing European designs (such as the Philips SDS 252, SRM 120 and SRM 120/X), the firm created new design which had several unique characteristics: it was modular; it had changeable optics; gear was housed in a separate module; it cut down on spares stock; it was easily serviced with parts being easily replaced; and the final design was polished off by leading Industrial Designers (Tony Butowsky and B. Rogers). In short, it was so revolutionary, Philips didn't even feel the need to give it a name in their catalogues and advertising – it was just the "MA" and that was the end of it. The first adverts appeared in multiple page spreads in 1975. The modular family of lanterns, comprising 90W, 135W and 180W versions, was made of three main modules: a GRP canopy, prismatic acrylic bowl and shoe (which could optionally be fitted with gear). Optical characteristics could be changed from semi-cut-off (the major system used in the UK) to cut-off by simply repositioning the lamp. And being based on LPS, the lantern could also boast its energy efficient credentials, being based on the most efficient light source at the time. In short, it was a winner. Uptake was brisk. It was used in the new motorway schemes and dual carriageways during the 1970s, and started to be used for major traffic routes, arterial schemes and dual carriageways in the 1980s. By the 1990s, it has also established itself as the replacement lantern of choice, with the smaller 90W model being used in many towns and cities. It probably became the most popular LPS luminaire in the UK for lighting main roads. Changes over its lifetime were minimal. The minimal gearless shoe, which was just a design embellishment, was joined by a brute, functional spigot, which changed the lantern's flowing lines, and was obviously a nod to budgetary constraints than design. Gear was also moved into the lantern's canopy itself; this made servicing easier but again ruined the appearance of the lantern. And a fifth clip was added to the tip of the canopy, probably the result of experience, and a requirement to prevent dust, water and insect ingress. It was a dominant force in the lighting industry for decades. But its demise was not due to a superior model or better design, but another revolutionary change in the industry. Most were lost to LEDification in the 2010s, as huge replacement schemes saw the lantern replaced in swaths by LED. But these lanterns, rightfully awarded an Industrial Design Award winner in 1975, showed that given an opportunity, the right design team, and an exemplary design, could be dominant on the UK's road for over forty years.

This lantern came from the first batch of lanterns I received from Balfour Beaty when the Cambridgeshire-Northamptonshire PFI started.

The top row of lanterns came from Kings Street, the bottom two rows were removed from Bateman Street and the rest were taken from Newmarket Road.