Liz TrussLiz Truss ©Richard Gardiner/Rex

Defra secretary Liz Truss has questions to answer over the failure of the government’s £154m computer system for farm subsidy payments, says an influential committee of MPs.

Ms Truss and Rural Payments Agency chief executive Mark Grimshaw have both been summoned to appear before the House of Commons Environment, Food and Rural Affairs Committee.

See also: We will make payments on time, insists minister

They will give evidence to the committee on Wednesday (25 March).

The agency announced last week that its IT system – which took two years to develop – was incapable of receiving farmers’ claims for the new Basic Payment System.

Farmers are now being asked to go back to pen and paper to complete their applications, although they are still being asked to register online for payments.

The U-turn follows months of warnings from farm leaders about the capability of the system to manage complex information – including mapping land.

Brussels has given farmers an extra month to complete their claims by extending the deadline for applications from 15 May to 15 June.

If claims are made on time, the government insists it will still be able to make subsidy payments to farmers after the six-month window opens in December 2015.

But it is unclear when exactly payments will appear in farmers’ bank accounts.

In recent years, farmers have received payments soon after 1 December. But the agency has stopped short of saying that will be the case this time round.

European Union rules mean the agency can legitimately make payments any time between 1 December and the end of June 2016.