Last month’s decision to leave the EU has put the brakes on plans to speed up and improve the region’s rail service – and has prompted current operator Abellio to reconsider its bid for the long-term contract according to a national newspaper.

The Sunday Times reported that Abellio had been lined up to run services in the region under a long-term franchise, but all the bids had been based on a “remain” vote in the referendum and the economic stability that would bring.

The company, which is owned by Dutch Railways, was alarmed by the slump in sterling after the Brexit decision, and feared that its profits could be reduced by 15% – forcing it to ask for more talks with the Department for Transport.

Abellio was competing with National Express and First group, both of which had operated services in the region in earlier years, for the new long-term franchise.

The DfT made it clear it would need to see bids which involved new trains on the main line from Norwich to London through Ipswich and Colchester – and also wanted to see major improvements on cross country and branch line services, especially the routes from Ipswich to Peterborough and Cambridge.

The announcement about the new franchise holder had been due to be made by the end of June, although it was made clear it would have to wait until after the referendum vote.

A spokeswoman for the DfT described the Sunday Times story as “pure speculation” and said an announcement on the franchise would be made “in due course.” She could not give any indication of a timescale for the decision.

The new long-term franchise is due to start in October, and it is thought that the new company will need at least three months’ preparation before taking over – although if the incumbent wins this might not be such a major issues.

Major improvements to the region’s rail services were included in the franchise requirement following a campaign spearheaded by regional MPs and business leaders.

One of the MPs who led the campaign, Ben Gummer from Ipswich, has been in contact with Claire Perry to try to find out when the decision might be announced.

He said he knew a delay to the decision could be a consequence of the Brexit vote, but still hoped that the current timetable for the new franchise could be achieved.

Abellio has been running trains in the region since early 2012 when it took over a short-term franchise for two years after previous operator National Express failed to get an extension.

This short-term contract was extended in 2014 under a deal which is seeing the main line carriages being refurbished – but real speed increases will only come when new trains are introduced, but that can only happen when a company has the security of a long-term contract.

The Abellio group was not able to comment on the story in the Sunday Times.