TONY Blair will warn this week that Britain's future prosperity relies on the country remaining a committed member of a strong European Union.

Amid mounting Tory calls for the UK to draw back from the EU, or even leave altogether, the former prime minister will urge the Government to remain fully engaged at the top table of European politics.

The Coalition is committed to renegotiating Britain's relationship with Brussels and winning back powers, while a smaller core of EU members of the euro move towards closer union.

The eurozone debt crisis has given new impetus in recent years to demands from many Conservatives for an in/out referendum on UK membership of the EU. But, in a speech in London on Wednesday, Mr Blair will warn against incremental changes and call instead for a "grand plan" that does not imperil Britain's economic prosperity.

An aide said: "He will outline why Britain needs to be at the top table and why, in all the detailed negotiations, it's important to not lose sight of the economic benefits that being part of a strong EU brings."

Mr Blair will stress that 47% of British exports go to other members and that 50% of foreign direct investment to the UK is from the EU.

Brussels talks on the next seven-year EU budget broke up on Friday without a deal, with Mr Cameron warning Europe has to live in the "real world".

Former Labour foreign secretary David Miliband said other EU members are angry with Britain because it does not take Europe seriously enough.

He told BBC1's Andrew Marr Show it is a "tragedy" that it has taken the Coalition Government two years to discover it has "allies in Europe" after Germany, Sweden and Denmark came out in support of the UK in budget negotiations last week.

"Britain is better off in Europe and, critically, Europe is stronger with Britain in it," he said.

"I cannot over-emphasise the sense of disappointment on the continent at us not being part of the European debate in a serious way."