Dangerous arrogance or an essential show of self-confidence? Only Boris Johnson, still on his travels abroad, knows why he chose to goad his critics back home with talk of a third term, but he has.

It was enough for Margaret Thatcher to say in 1987 she hoped to “go on and on” for the rebels in her party to redouble their efforts to oust her. Yet it was another three years before they managed it.

Mr Johnson, judging by his tone during the Commonwealth summit in Rwanda, is in no mood to panic and rush home. Despite a double by-election loss, he saunters on to a G7 get-together in the Bavarian Alps and a Nato meeting in Madrid.

He still has the same problems as before, chief among them the cost of living crisis and the continuing fallout from Partygate, but he is approaching them in a different way. As he put it: “You have to try to distinguish between criticism that really matters and the criticism that doesn’t.”

It is a good rule for any politician, and one that Brandon Lewis, Northern Ireland Secretary, applied when he was once again wheeled out as the Minister for the Sunday shows.

As Trevor Phillips put it on Sky News’ Ridge on Sunday, Mr Lewis was notable for being one of “the most normal members of the Cabinet”. The same was said of Oliver Dowden. After last Friday’s dawn resignation of the Consevative co-chairman, that leaves Mr Lewis in a lonely position. Judging by his laughter at Phillips’ description –“I think I’ll take that as a compliment”– he retains that much-needed sense of humour.

So when asked by Phillips, and later Sophie Raworth on BBC1’s Sunday Morning, if the Prime Minister was serious in his talk of a third term, Mr Lewis praised his boss’s “zest and enthusiasm”, and his proven record as an election winner.

On Michael Howard saying the party and country would be better off under new leadership, Mr Lewis referred to the former leader as someone “who sadly wasn’t able to win an election”.

Also in the mood to be decisive was David Lammy, the Shadow Foreign Secretary, though the strategy worked better on some topics than others. There would be no pacts with the SNP, no pacts with the Liberal Democrats, and no pact with the Greens, he told Sunday Morning. Simple.

The going got trickier when he was asked about his party’s stance on the rail strikes, and some Labour politicians joining picket lines in defiance of the leadership’s instructions.

The MP was able to put some distance between the rail strikers and the party by pointing out that the RMT was not affiliated to Labour. But would Labour support BA staff being balloted on strike action by the GMB and Unite unions – both affiliated? That was a no, eventually.

“All of us are feeling the pinch with inflation,” he told Raworth. “Many of us might want a (pay) rise of 10%; in truth, most people understand it’s unlikely that you’re going to get that.”

Asked whether he supported the proposed strike by airport check-in staff, Mr Lammy said: “No, I don’t. No I don’t – it is a no, it’s a categorical no.” Why? “Because I’m serious about the business of being in government and the business of being in government is that you support negotiation.”

There was no mention in either of the main shows of treehouses. Why should there be, you ask? The Times on Saturday reported that the Prime Minister and his wife wanted to build one at Chequers for their son, Wilf, but were dissuaded by an estimated bill of £150,000. While the story attracted a lot of attention on social media, most mainstream media steered clear.

On BBC Scotland’s The Sunday Show it fell to Douglas Ross, leader of the Scottish Conservatives, to once again set out where he stood on Boris Johnson’s leadership. Given his wavering stance previously – you’ve been all over the shop, said presenter Martin Geissler – it was as well to check.

Mr Ross was back on the anti-Johnson side. But what to do about that when the Prime Minister said he was “thinking actively” about a third term?

“Clearly there will be discussions among colleagues,” said Mr Ross, flagging up forthcoming elections to the 1922 committee of backbenchers which could change the rules and allow another challenge. He did not, however, believe the rules should be changed midway through a process.

To apply the Prime Minister’s test, did Mr Ross’s criticism matter, or not? Given his response to previous advice from the leader of the Scottish Conservatives, that was the day’s easiest question to answer.