Sacked defence minister Tobias Ellwood has urged Boris Johnson to “step back from the rhetoric” in his dealings with Brussels to ensure the country does not crash out of the EU without a deal.

The former army officer was a casualty of Johnson’s ministerial cull as he took over at Downing Street this week and sought to shake up his government team.

The new prime minister has repeatedly pledged to take the country out of the EU on 31 October even if he fails to agree a deal with Brussels.

But Ellwood – who backed remain during the 2016 referendum – has been a firm no-deal critic, saying before his sacking that such a scenario “isn’t a solution”.

The Conservative MP, who bravely tried to save the life of PC Keith Palmer after he was stabbed during the Westminster terror attack, said he was shocked at his sacking.

Giving his first interview since being axed, Ellwood told BBC Radio 4’s Today programme that it was a “brutal game”, adding: “But it is a recognition that that is the world we enter when we sign up to politics.”

Despite being shown the door by the prime minister, he called on fellow Tory MPs to back Johnson to get Brexit “over the line” and said he should be given a “fair wind”.

However, asked about the strong rhetoric used by Johnson – who has said the country must “turbocharge” preparations for a no-deal Brexit – Ellwood replied: “My one first bit of humble advice might be, let’s step back from the rhetoric that we saw on the campaign trail. Lots gets said, as we know, in modern day politics, lots gets tweeted about as well. The two sides have not yet met.

“There is a recognition that you can’t escape. The legal entity here, buried in the article 50 letter, unfortunately, is that if you don’t secure a deal you end up with no deal. I think that was a mistake to write it in that letter.

“I think if the letter had said if you don’t secure a deal, you remain in the EU, I think we would have been out last March. But that isn’t the case. What we have is a time period here just less than 100 days. We’ve got the G7 summit, we’ve got meetings that are taking place. We have the EU council meeting as well that is in October. These are opportunities to secure a deal and to make this work.”

In reference to comments made by Simon Coveney, Ireland’s deputy prime minister, that Johnson’s approach to Brexit talks was putting the UK “on a collision course with the EU”, Ellwood again warned it would be good to “dial down” the rhetoric.

Although the Tory MP said he was optimistic of Britain reaching a Brexit solution, he conceded it would be difficult for Parliament to stop the country leaving without a deal.

Referencing the DUP – who he said were “desperate to climb down from the ladder that they’re up” – and 25 Labour MPs in Brexit-voting seats, he said “the numbers are there to be found” to get a deal through parliament.

“We’ve heard overtures from the European Union, such as Ursula von der Leyen, who want to say ‘let’s make this work’. It’s in everybody’s interest to get a win here and secure and deal and that, I think, is what we should focus on.”