Alexander Downer said there was too much 'gloom' about the prospects of Britain and the EU striking a deal

Britain should be more positive about life outside the European Union, Australia's high commissioner to the UK said today.

Alexander Downer said there was too much 'gloom' about the prospects of striking a deal and Britain could be 'cautiously optimistic'.

Mr Downer pointed to Australia's policies when Commonwealth preferential trade agreements were ended as a template for how the UK could thrive.

He told BBC Radio 4's Today programme: 'I think you are a bit gloomy.

'Of course this is a big transition that you're going through and there's much contention about the negotiations, which are negotiations.

'But our experience of major changes like this, and we had such a major change as the Commonwealth preference system was phased out and eventually Britain joined the European Union in 1973, that you are going to succeed depending on what policies you pursue subsequently.'

He said it was possible for the UK to conclude a successful negotiation with the EU.

'You have a motive to conclude a successful negotiation, so does the EU, so prima facie you have some basis for being cautiously optimistic that an agreement ultimately can be reached,' Mr Downer said.

'It'll involve compromises though, so both sides won't get exactly what they want.'

The high commissioner also said Australia's experience showed it was possible to do new trade deals without accepting free of movement of people.

He added: 'As outsiders we're very anxious that both the EU and you do reach an agreement.

'Not just the UK of course, the onus is on the EU as well to make sure you don't erect barriers.

George Osborne, pictured enjoying a post of tennis at Wimbledon last month, was accused of being too pessimistic about Brexit by his former chief of staff

Rupert Harrison, george osborne's former chief of staff, said the former Chancellor is being too gloomy over Brexit

'But secondly, it seems to us from our own experience that if you in addition, not instead of, but in addition, to that go out and negotiate trade arrangements with other parts of the world, you can make your approach more global and less regional than it might otherwise be.'

The comments came after George Osborne came under fire from a former senior aide for his pessimism about Brexit.

Rupert Harrison - who was nicknamed ‘the real Chancellor’ during his five years in the Treasury - dismissed the ‘fashionable view’ that the government had displayed a ‘lack of strategy’.

He warned the ‘main uncertainty’ about the success of Brexit was not talks with Brussels but MPs and ‘angry’ peers in Parliament.

Mr Harrison also said it was a ‘non-starter’ for the UK to leave the EU but try to stay in the single market – a key demand of ardent remainers.