Japans warns UK of job losses if it leaves EU

In a written submission to the UK as part of the review revealed over the weekend, the Japanese government said that 1,300 Japanese companies had invested in the UK, creating over 130,000 jobs.

"This fact demonstrates that the advantage of the UK as a gateway to the European market has attracted Japanese investment," it stated, adding that it expected that "the UK will maintain a strong voice and continue to play a major role in the EU."

The UK is keen for the EU to shift its priorities towards trade promotion such as the just underway negotiations with the US on a free trade agreement.

Meanwhile, talks aimed at securing an EU trade deal with Japan, the world's third largest economy, are also expected to start formally in the coming months.

For its part, the US government has also repeatedly cautioned the UK against leaving the EU.

Foreign secretary William Hague launched the 'balance of competences' review in July 2012 claiming that it would serve as an audit of EU policy making across a range of areas but would not bind the government in negotiations.

Over 30 separate reports covering policies ranging from trade and the single market to foreign and development policy are expected to be published between now and autumn 2014.

The conservative/liberal coalition has also adopted legislation to create a 'referendum block', meaning that all future EU treaty changes involving further transfers of power to Brussels would be subject to a public vote.

A government memo launching the review commented that it would serve as "an audit of what the EU does and how it affects the UK."

"It is important that Britain has a clear sense of how our national interests interact with the EU’s roles, particularly at a time of great change for the EU," it added.

Earlier this year, prime minister David Cameron outlined plans to renegotiate the terms of the UK's EU membership and then hold an 'in/out' referendum if his Conservative party wins the next election.