Former PM Gordon Brown warned that leaving the EU would turn Britain into Europe 's North Korea . Britain would turn into the European North Korea if it left the EU , Gordon Brown has claimed . In a bizarre warning ahead of a speech to the Commons tomorrow , the former Prime Minister said the UK would be 'left out in the cold with few friends [ and ] no influence ' like the regime in Pyongyang . He rejects claims that Britain could succeed on its own by becoming an open , trading nation like Switzerland or Hong Kong . But the warning that Britain would fall into North Korean isolationism is likely to spark ridicule . A report commissioned by Boris Johnson last year said leaving the EU was 'definitely a viable option ' for the UK . Mr Johnson 's chief economic adviser Gerard Lyons said the best option was to stay in a reformed European Union – but if that could n't be achieved exit was better for the economy than the status quo . But in a startling intervention ahead of tomorrow 's House of Commons debate on the EU , Mr Brown said : 'We must tell the truth about the 3 million jobs , 25,000 companies , £200billion of annual exports and the £450billion of inward investment linked to Europe . ' He said leaving the EU but staying in a free-trade area could leave us 'subject to EU rules , but denied a vote in shaping them ' . The former Labour leader , who is stepping down as an MP in May , also dismissed the 'Hong Kong option – leaving Europe to join the world . He said this was 'really the North Korea option – out in the cold with few friends , no influence , little new trade and even less new investment ' . In a bizarre warning ahead of a speech to the Commons tomorrow , former Prime Minister Gordon Brown said the UK would be 'left out in the cold with few friends [ and ] no influence ' like North Korea under Kim Jong-un . Mr Brown , writing in the Guardian , said Britain should not contemplate exit when it was on course to overtake Germany as the EU 's largest economy . He said : 'It would be sheer defeatism to cast ourselves , as sceptics do , as helpless victim , impotent bystanders unable to influence events . 'Our destiny is not a bit player on someone else 's stage , or a spectator hectoring from the wings , but always setting the agenda , bringing people together , and championing change . ' He added : 'Being half-in half-out , a Britain that is semi-detached and disengaged – the Britain of the empty chair even when we are in the room – has made us weaker than ever : irrelevant on Greece , fringe player on climate change , mere spectator in the debate that could have shaped a European pro-growth policy , marginal on Ukraine , with ministers sounding ludicrous as simultaneously they say : 'Russia must be confronted with a more united Europe ' , and : 'By the way , we are thinking of leaving . '
Former PM rejects claim Britain could succeed on its own outside the EU . Dismissed suggestion UK could be an open , trading nation like North Korea . He said this was 'really the Hong Kong option ' with Britain isolated .