Gordon Brown will today vow to resist moves to impose shorter working hours on Britain and will attack the economic management of the European Union.
In his first speech since the election, the Chancellor will deliver a grim verdict on the health of the economy in the eurozone, which he will argue has lagged behind Britain and the US.
He will signal that economic reform will be the Government's top priority when it assumes the presidency of the European Union on 1 July. Following the European Parliament's vote to scrap Britain's opt-out from rules banning employees from working more than 48 hours a week, he will argue that encouraging flexibility in the labour market is essential for prosperity.
Mr Brown will reject the concept of the EU as an introspective trade bloc in a speech to the Confederation of British Industry's annual dinner in London.
He will say: "Britain must and will promote labour, product and capital market reform in Europe. And in our presidency of the EU we will push forward our proposals to liberalise the single market and make the European economy more dynamic.
"Our aim is a Europe that, instead of being a trade bloc looking inward on itself, looks outward, engages with the rest of the world and reforms and liberalises to meet the global challenge.
"Our proposed agenda will be labour market reform, so we will resist the opt-out to the 48 hour week being removed, and product and capital market liberalisation, so you have access to European markets."
Mr Brown will argue that Britain has achieved an economic framework that had withstood a doubling of oil prices and a trebling of the cost of basic materials, from steel to cement. In any other decade, he will say, that would have led to a "severe inflation shock".
The Chancellor will announce he has asked a European committee, chaired by the senior Labour MP Barry Sheerman, to report on whether a consensus can be built between the British political parties on how best to reform the EU economy.