Gainsborough was set up by Dr Humfrey Chamberlain and Peter Pettit of Chamberlain & Pettit agricultural merchants in Burkitt’s Lane in Sudbury, 1960 (or just before). I’m assuming it was named after Thomas Gainsborough who was Sudbury’s most famous figure. Initially they used a simple ‘GP’ logo but later switched to the orange and blue G sign. The petrol was cheaper than major brands and I think given the fervour for Jet’s price-cutting that was often in the newspapers at this time, there was probably a strong appetite for discount petrol to come to the area, although Ben Cooper’s Little David, based at Claydon, had also started as a slightly discounted brand in the 50s.

Humfrey Chamberlain had worked as a researcher for Shell after a PhD in chemistry at Cambridge in 1949, then become a lecturer at Leeds University, before going into farming in the mid-50s and then partnering with Peter Pettit. Chamberlain & Pettit had a lot of business interests including being International Harvester dealers. Supplying agricultural diesel and TVO (making deals with oil companies, given Chamberlain’s background) probably led naturally into selling their own brand of petrol (I don’t know who they bought it from at this point).

Gainsborough expanded quite rapidly supplying independent garages across East Anglia and the home counties and at some point in the mid-sixties Chamberlain & Pettit sold out to Sinclair Oil, a US company, who were breaking into the UK market. They then in turn merged with Atlantic Richfield in 1969; Atlantic Richfield kept the Gainsborough brand rather than replacing it with Arco (I think because it was so strong in East Anglia — e.g. at the end of 1969 there were 280 Gainsborough sites, compared with only 70 Atlantic and 97 Abco, the other brands in the merged group which got converted to Arco). But when Total bought Atlantic Richfield’s UK petrol retailing business in 1974 they switched everything to Total (and probably in time ditched a lot of the smaller ex-Gainsborough sites in East Anglia).

Humfrey Chamberlain had lots of other interests including gliding and flying, the Hydrocut log splitter— https://www.hydrocut.co.uk/ , a signage company which became https://sasl.co.uk/ , and with his wife Ruth and two friends who had worked for the Ramblers’ Association, setting up Waymark Holidays, a travel company.