The election campaign will be the “most dishonest in modern times” because both main parties refuse to debate the consequences of Brexit, a former Tory deputy prime minister has said. Michael Heseltine, who was deputy prime minister from 1995 to 1997 and a senior figure in Margaret Thatcher’s cabinet, said no key problem affecting the country can be “honestly addressed” without considering the impact of leaving the EU. Writing in the Independent, Lord Heseltine said: “We are now at the start of what I foresee will be the most dishonest election of modern times. “The state of our economy, defence and environment, the need to level up our society, control immigration and restore Britain’s standing in the world. None of these issues can be honestly addressed in isolation from our relationship with Europe. Yet Europe is the no-go area,” said Heseltine, who fell out with the Conservative party during the run-up to the Brexit referendum because he wanted to remain in the European Union. “Why cannot the two major parties debate immigration in the round? The boats contain just 5% of those who might or might not be sent to Rwanda. They are a small part of the near-700,000 net immigration figure – the real elephant in the room.” He said Britain needs to work more closely with its “European neighbours, who share our experiences”. “Until we consider the consequences for our farms, care homes, hospitals and universities of culling the numbers, all the talk of change, the constant assertion of ‘plans’ amount to little more than platitudes blowing in the wind.” He added that Britain might not be able to rely on Nato if the former US president Donald Trump is re-elected, thus needing a closer defence relationship with Europe. Heseltine made the comments as the general election campaign continues. Labour and the Tories have clashed over security after the Conservatives announced a pledge to introduce national service. In a keynote speech Keir Starmer has said that “economic security, border security, and national security” will form the “bedrock” of the Labour party’s manifesto. Rishi Sunak is expected to reinforce his message that the Conservatives will take “bold action” to deliver “a secure future for the next generation”. The Tories have said that all 18-year-olds would be made to undertake a form of “mandatory” national service if the party is re-elected on 4 July.