Most of East Anglia’s trains are sub-standard, and the new operator that takes over the franchise next year will have to replace them.

That’s the blunt message from the government in the prospectus for the East Anglia Rail Franchise which was unveiled just hours after Prime Minister David Cameron announced the government’s long term economic plan for East Anglia.

The franchise document published by the Department for Transport says: “The current fleet is generally below the standard expected and this franchise will seek to secure significant investment in the quality, condition, design and reliability of the trains on the Anglia region.”

It does not say that the trains will have to be new – but it does say they will have to achieve the aims of the Great Eastern Rail Campaign of running between London and Norwich in 90 minutes, in Ipswich in 60.

Ipswich MP Ben Gummer said these conditions, in effect, meant new trains would have to be ordered for the InterCity services because there were no units anywhere else on the rail network that could meet these requirements.

He said: “This is a very good document. It leaves no doubt that there will have to be new trains on the main line, running on improved tracks and providing a faster, more reliable service.”

The franchise looks like a prize for any operator – between 2007 and 2013 the number of passengers increased by an average of 3.5% a year.

In her foreword to the prospectus rail minister Claire Perry says: “The East Anglia franchise presents the opportunity to give passengers a great experience of the railway, be that at stations or on trains.”

She adds: “We want an operator that will deliver advanced solutions to provide high quality, stylish, modern rolling stock that is accessible to all the franchise’s passengers.”

However the opposition claimed the absence of any explicit mention of new trains for the region was significant.

Shadow rail minister Lilian Greenwood said: “David Cameron’s claim that he is improving East Anglia’s rail network is a sham.

“Since 2010 investment has been held back by short term contracts on the route and not a penny of new funding has been allocated by the Government for the next Parliament.

“Worse still, this announcement sees Ministers row back on their previous assurances that there would be new trains for East Anglia. Passengers deserve better, but only Labour is committed to reforming the railways and putting passengers first.”