Researchers increasingly think that our Circadian rhythm, or body clock, matters more to our sleep than we realise. In fact, one study suggested our internal rhythm might matter more than sleep duration when it comes to feeling rested.

And in an Australian paper, which was published in Sleep Medicine, researchers found that people who struggle with racing thoughts that keep them up at night seem to have differences in their Circadian rhythm.

“Unlike good sleepers, whose cognitive state shifted predictably from daytime problem-solving to nighttime disengagement, those with insomnia failed to downshift as strongly,” the study’s lead researcher, Professor Kurt Lushington, said.

In this research, scientists placed 32 adults (half of whom had insomnia; the other half were healthy sleepers) in an environment with as few external body clock cues as possible.

They were placed in a bed in a dimly-lit room for 24 hours, with carefully-measured food and activity. This was done to isolate the participant’s Circadian rhythms.

The scientists noticed that, even with no factors like sunlight, most participants’ body clock worked roughly in tandem in the daytime: their mental acitivty was highest in the morning and tapered off in the afternoon.

But among the insomniacs, whose racing thoughts kept them up at night, some differences were noted later on.

Not only was their “cognitive peak” – the time at which their mind was busiest – 6.5 hours later, on average, than those without insomnia, but, Dr Lushington said, “Their thought patterns stayed more daytime-like in the nighttime hours when the brain should be quietening”.

Sleep, he added, is “about the brain disengaging from goal-directed thought and emotional involvement.

“Our study shows that in insomnia, this disengagement is blunted and delayed, likely due to circadian rhythm abnormalities. This means that the brain doesn’t receive strong signals to ‘power down’ at night.”

According to study co-author Professor Jill Dorrian, this research could help to guide insomnia treatments which focus on sufferers’ body clocks in the future.

“These include timed light exposure and structured daily routines that may restore the natural day-night variation in thought patterns,” she said (sleep experts have previously recommended getting some outdoor morning light if you can, as this helps to regulate our Circadian rhythm).

Additionally, Professor Dorrian ended, “Practising mindfulness may also help quieten the mind at night”.

John Healey has refused to say whether the UK government backs the US and Israeli bombing of Iran which killed the country’s Supreme Leader Ayatollah Ali Khamenei.

The defence secretary would only confirm that Britain “played no part” in the military action.

Iran’s paramilitary Revolutionary Guard confirmed in the early hours of Sunday that Khamenei had died, and said it would launch its “most-intense offensive operation” against American and Israeli targets in response.

That led to Donald Trump warning they “better not do that, because if they do we will hit them with a force that has never been seen before”.

Countries across the Middle East have already been attacked by Iran as tensions in the region threaten to explode into a full-blown war

Nevertheless, Healey refused to be drawn on the government’s position when asked by the BBC’s Laura Kuenssberg.

She asked the cabinet minister whether he thought the American and Israeli action was “reckless or do you think it was right”?

Healey said: “We played no part in these strikes as Britain.”

But Kuenssberg told him: “We know that, you’ve said that already. But this is a moment of history.

“Everyone watching this morning will want to know and expect to know from their government is Britain on the side of those two countries who have killed Iran’s Supreme Leader?”

Healey said: “I think people watching will want to know now, today, that Britain is on top of what’s necessary to do what we can to keep them safe, to reinforce regional stability, prevent further escalation, and that’s my task and that’s my priority as defence secretary of the UK.”

The US and Israel described Saturday’s attacks on Iran as a “pre-emptive” strike against a Tehran government intent on developing nuclear weapons.

It retaliation from Iran, with strikes reported in several Gulf countries including the United Arab Emirates, Qatar, Bahrain and Saudi Arabia.

In a statement from Downing Street on Saturday, Keir Starmer said the UK “played no role” in the strikes on Iran.

“But we have long been clear – the regime in Iran is utterly abhorrent,” he added.

“They have murdered thousands of their own people, brutally crushed dissent, and sought to destabilise the region.”

Starmer said Iran “must never be allowed to develop a nuclear weapon” and called for the resumption of diplomatic efforts to prevent that from happening.

He said: “Iran can end this now. They should refrain from further strikes, give up their weapons programmes, and cease the appalling violence and repression against the Iranian people – who deserve the right to determine their own future, in line with our longstanding position.

“That is the route to de-escalation and back to the negotiating table.”