A group of Nisa shopkeepers hope to block the Co-op’s £143m takeover of the convenience retailer.

Nisa shareholders will vote next week on the deal but members opposed to a deal believe that the terms being offered are unfair, The Sunday Times reported.

A deal between the Co-op and Nisa was agreed in October, following a decision by Sainsbury’s not to proceed with an acquisition of the c-store and buying group.

Nisa members would each receive £20,000 in cash when the Co-op tie-up is completed.

They would then be paid the outstanding £137.5m over a four-year period.

According to City sources, most Nisa members are in favour of the Co-op’s offer.

However, a group of rebels are speaking to lawyers about stopping the deal. They argue that its structure favours smaller shareholders.

They claim that at a meeting in June, the Co-op indicated members with the maximum number of 250 Nisa shares would receive £100,000 upfront.

A source close to the deal told the newspaper that the talk of opposition was “mischief-making” by a small group whose “actions are at odds with the interests and desires of the wider membership”.