It held an launch party in September, opened its doors in June and this newspaper saw the shop being fitted out in May.

But the developers who have turned the Leighton Arms pub into a supermarket are now arguing with Camden Council over when the shop actually opened.

In an appeal to the planning inspectorate, Bryanston Investments, say it was operating in August 2017.

Earlier this year Camden Council slapped developers Bryanston Investments with an enforcement notice, demanding the Nisa supermarket which has been operating since June is closed and the alterations to the building are reversed.

But the developers are disputing this, as the work was carried out legally, under permitted development rules.

They also argue that planning permission for the move should be granted retrospectively and that they were not given enough time to comply with the council’s enforcement order anway.

Permitted development rules require the developer to inform the local planning authority – Camden – of their plans, and to implement the change of use within a year.

Camden argue they did not receive the letter Bryanston claim to have sent to them on August 9 2016, but that even if it had received it, the shop was not operating by August 2017. They have submitted Google Streetview photographs illustrating the boarded-up building to the planning inspectorate as part of the case.

Bryanston have produced a letter from an accountant, stating their tenants were retailing from the building in autumn 2017.

However, the town hall has no record of business rates being paid then.

Campaigners including Camden’s mayor Cllr Jenny Headlam-Wells and Charles Dance have opposed the Nisa and still hope to save the pub.

Local activist Jo Siedlecka said: “It’s hard to believe. The shop wasn’t open then.”

One of Bryanston’s directors, Martin Cramer, told this newspaper: “Everything we are saying is true. It’ll all be clear. We’re just going to wait for the proper process.”