Aveling & Porter of Rochester, Kent are believed to have been the first company to produce a Tandem steam road roller - tandem refers to the fact it has two 'rollers', as opposed to the traditional 'three point' roller which involves one main roller, usually at the front, and two rear wheels which although built like rollers are much narrower - as more weight is at the rear, which is accentuated by the narrow wheels, it forces down on the surface more which makes an uneven surface. As well as having a secondary main roller at the rear, it also has the water tanks near the centre of the engine, increasing the weight distributed by the front roller. This design was introduced in 1902 and produced until 1920 when they started to make them in the American fashion, with a vertical boiler carried between the two rollers.
This 1908 built Aveling & Porter Tandem, works number 6530, registration NM 291 and named 'Bernard', was bought new by Luton Corporation and is the earliest surviving tandem steam roller in the UK, and most likely the world. It is believed that it was ordered to work in Luton over the roadways where the electric tram system, opened in 1908 also, ran. 6530 worked for Luton Corporation until the 1950's. After being sold out of service it worked at a construction site in Luton, and is also believed to have last been used to work on the M1 Motorway. It is owned by Luton Cultural Services Trust, and is usually an exhibit at Stockwood Museum in Luton. It currently requires a new firebox before it can return to steam, for which fundraising is underway and donations gratefully accepted