Witham MP and home secretary Priti Patel has hit out at rail firms over reports the rollout of new Bombardier trains for some suburban services in her constituency have been delayed until autumn.

The first of Greater Anglia's new trains serving stations in the Witham area were expected to enter service later in the spring - with the full rollout completed by the end of 2020.

The Bombardier Aventra trains are due to take over all electric suburban services in the region.

They will form the trains from Liverpool Street to Colchester, Clacton, Harwich and Braintree.

Some will also reach Ipswich on suburban trains.

MORE: New trains start to arrive on Greater Anglia networkHowever, it is understood the full rollout is expected in late summer to early autumn due to software issues - with the trains unlikely to be phased in completely for a further 12 to 18 months.

Ms Patel called for any financial penalties imposed on Bombardier over a failure to deliver the new trains on time to be passed onto commuters, adding: 'I led efforts to secure over £1billion for these much-needed new trains and I am extremely disappointed that the rollout of the new Bombardier trains is to be delayed until the autumn.

'This significant delay is unacceptable and Greater Anglia needs to take urgent action to resolve the outstanding software issues as a matter of priority and to ensure the rollout of these new trains is not delayed any further.

'I have called on Greater Anglia and the secretary of state for transport to challenge Bombardier and impose financial penalties for the failure to deliver the new trains in line with contractual obligations.'

Testing phase 'essential'

Bosses at Greater Anglia said Bombardier has now built 231 of 665 carriages. Two of the trains are now on the network, and testing is due to start soon.

'There has been a delay to the project, which Bombardier says is due to a range of factors including software development,' a spokesman said.

'It is essential we and Bombardier get the build and testing phase right, so that when the trains enter passenger service they are reliable so they can improve the performance of our railway, as well as provide a much better travelling experience for our customers.

'We are working closely with Bombardier and are confident that the new trains will start to enter passenger service later in the year, as soon as they are ready.'

A Bombardier spokesman added: 'We are committed to getting these state-of-the-art Aventra trains into service with Greater Anglia as soon as we possibly can. We have two of our six production lines at our Derby factory dedicated to the project and have recruited 400 extra staff since December to help speed up production.'