All petrol and diesel is produced by everyone to a set regulated specification for a particular standard e.g. 95RON, 99RON etc.
Whether it be branded Shell, Esso, BP, Morrison, Sainsbury, Apple, Chevron, Tesco or whoever, the base product is exactly the same. The only difference between brands is the additives each brand adds.
The supplier and distributor for Tesco and Esso fuels is the same. The additives will be different.
https://www.greenergy.comGreenergy is the distributor in UK for Esso.
https://www.greenergy.com/essoTesco is a major shareholder in Greenergy, the distributor for the Esso brand.
https://www.theguardian.com/business/2010/nov/28/tesco-petrol-retail-industryI am not sure any oil majors now do their own distribution of the finished product or even refine it for their own exclusive sale as they used to or now even own their own refineries. Think Ineos.
So the refining and distribution of fuel is now an open secondary market not operated by the oil majors. Most of the oil majors now only franchise out their brands to retail site owners.
And there is a very close distribution relationship between Tesco and Esso via Greenergy. Same unliveried tankers I expect.
All base petrol and diesel fuel is exactly the same. Different brands add different additives when the tanker is loaded at the common distribution source for delivery to their own branded retail sites. So an Esso liveried tanker may deliver to Tesco. If it is delivering to Tesco, it is not delivering Esso fuel!
(Geenergy are also working with Shell on the Thames Oil Port:
"Thames Oilport
We are building Thames Oilport on the site of the former Coryton refinery in the UK, as a joint venture with Shell. We are turning the former refinery into a modern import [distibution] terminal capable of meeting growing fuel demand in the South East of England".)
https://www.greenergy.com/manufacturing-and-infrastructureHope all that makes sense! Nothing is what it seems!
You pays your money and takes you choice.
Greenergy used to publish the analysis of their base products on their website – they may still do.
You’ll have to work very hard to find which brands add what additives and what they do (mostly detergents IIRC)!