Plans for an elected mayor for East Anglia and the devolution of Whitehall powers to the region could be set back for years if a consensus is not found by next Friday, the business boss leading discussions has said.

But the claim was undermined by the government saying there was no deadline, while there were also claims a three-county devolution deal was on the brink of unravelling and further calls for the election to be put back a year.

The chief executive of Adnams brewery, Andy Wood, who was elected by leaders in Norfolk, Suffolk and Cambridgeshire to lead talks, said the region could lose its place in the queue if an agreement was not reached by May 27.

But West Norfolk MP Sir Henry Bellingham claimed a three-county deal was dead.

He claimed there was an agreement between the Treasury and Department for Communities and Local Government that Cambridgeshire would go it alone with a mayor, and Norfolk and Suffolk were back on their own.

Since the March budget, when leaders signed a three-county deal, Cambrigeshire councillors have spoken of their unhappiness and former Norfolk County Council leader George Nobbs branded the process a 'shambles'.

But Dr Wood said Cambridgeshire was still at the table talking, with proposals for a separate mayor for Cambridgeshire 'under discussion'. He added: 'If we can't get agreement by Friday week, I do think that it could be that East Anglia misses out certainly in this round of devolution deals, but it could be that it sets us back for years – and that would be a great shame.

'Really, to be perfectly honest, the leaders get that and feel pressure around that and are doing what they should do, which is leading.

'There is no doubt that there are other regions of the UK in a queue behind East Anglia if East Anglia decides to step out of that queue.'

Norwich City Council leader Alan Waters said he had long argued that the timetable should run into 2018 to allow a thorough negotiation.

He added that they needed to understand what it would mean for councils to support a combined authority. More money would be needed if there were going to be two distinct deals and the original sums should not simply be split between the two areas.

'A longer lead-in time would make much more sense; it has been stymied by this sense of urgency the government has. That may be an obstacle in the end to cutting a deal,' he said.

Earlier this week Conservative county council leaders were accused of holding 'secret' talks with local government minister Greg Clark on devolution.

But Cliff Jordan, the newly-elected council leader, shrugged off criticism of the County Hall meeting between himself, his Suffolk and Cambridgeshire counterparts and the government minister. He said the meeting was primarily to bring him 'up to speed' on the ongoing devolution talks.