Cheryl Gillan is to call for an updated analysis of HS2's costs after major rail upgrade plans will be delayed.

Transport Secretary Patrick McLoughlin announced on Thursday work to electrify the Transpennine route would be "paused", with Network Rail admitting the project would cost more than originally thought.

Mrs Gillan said this raises questions as to the affordability of HS2, which will cut through her constituency.

Reports from 2011 and 2012 which raised concerns over the cost of HS2 were revealed the same day as Mr McLoughlin's announcement in the House of Commons. They had previously been withheld after Mr McLoughlin vetoed the decision to publish them.

Mrs Gillan said: "In the light of what was announced about the northern rail upgrade project cancellations, which described the projects as ‘undeliverable’, what does this mean for HS2? Will the HS2 project become undeliverable?"

The Chesham and Amersham MP said the reports should have been made available to MPs before they voted for the second reading of the High Speed Rail Bill in the last Parliament.

She added she will be writing to the chairman of the Major Projects Authority to ask for a fully updated analysis of HS2.