The senior Conservative MP behind Westminster's cross-examinations of the EU referendum campaign's economic claims has come out for Remain, with 10 days before the 23 June vote. Andrew Tyrie, the chair of the House of Commons' influential Treasury Select Committee, warned the UK would lose influence on the world stage if it split from the EU.

"My own view is that much of the control that might come, post-Brexit, would be illusory. Britain would still need to negotiate with the EU in pursuit of the national interest, whether in or out. It's called international relations," he wrote in The Times.

"From outside, the UK would lose influence over decisions that nonetheless profoundly affect the economy. Those who claim that this influence is illusory need to explain the UK's exemption from the eurozone, Schengen, the migrant quota system, banking union, among much else.

"The UK cannot dictate. And the EU can be a very frustrating place to do business. But Britain's influence is certainly not negligible."

Ukip donor Arron Banks, the co-founder of Leave.EU, declared "no surprise" after Tyrie announced his pro-EU position, claiming his cross-party group of MPs "was much harder on the Leave campaign". Banks, an insurance millionaire, was one of the witnesses to appear before the committee as part of its investigation into the EU referendum campaign.

The group of MPs criticised both sides of the Brexit debate for "inconsistent, unqualified and, in some cases, misleading claims and counterclaims". The committee particularly attacked the Vote Leave campaign, the official Brexit group, for claiming that the UK sends £350m ($496m) per week to the EU.

Arron Banks, Leave.EU co-founder

"By far the most prominent, and most controversial, figure for the UK's EU budget contributions is that of £350m per week, used by Vote Leave... it does not account for the rebate, or include any receipts from the EU budget," the group said.

Tyrie's declaration for Remain comes after fellow Tory Dr Sarah Wollaston, the chair of the Health Select Committee, defected from Vote Leave to a pro-EU position. Elsewhere, Crispin Blunt, the Conservative chair of the Foreign Affairs Select Committee, has announced his support for a Leave vote at the referendum.

The latest online opinion poll from YouGov, of more than 1,600 people between 9 and 10 June, put Leave just one point ahead of Remain (43% versus 42%), with 11% of respondents undecided.