Defeated, humbled, rejected, where does Donald Trump go from here.

The Republicans lost control of Congress in the US midterms, with the Democrats winning both the Senate and House of Representatives.

Trump was swiftly branded a “lame duck president” by one Democrat senator as the political earthquake rippled through America, across the Atlantic and beyond.

Lord Sadiq Khan fired off a stinging attack on Trump’s “damaging and divisive politics” as he praised US voters for turning their back on the president.

But London could soon be impacted by Trump’s response to the crushing election results, which could potentially lead to more Iran-backed attacks on the capital.

Trump initially struck an unusually conciliatory tone after the election losses, praising the Democrats for their campaign, while criticising Republicans.

He also signalled that he is ready to use his presidential veto as he heads towards political gridlock in Washington.

The clock, though, is now already ticking on his presidency and his attention will very quickly turn to legacy, or trying to shape one which he can trumpet as a list of achievements in office.

But Trump’s challenge lies in more than one capital; Tehran as well as Washington DC.

Unless he can end his Iran war, he will find it extremely difficult to better address the cost-of-living crisis being suffered by millions of households across America.

Gridlock in Tehran and gridlock in Washington will firmly tie Trump’s hands.

The US president acknowledged that the Iran war, driving up inflation and oil prices due to restrictions on shipments through the Strait of Hormuz, may well have contributed to Republican losses.

But he also made clear that he is ready to ramp up the US military campaign against the repressive and brutal Tehran regime.

"We have to do something large," he told Fox News, adding that it could involve a "heavy hit".

Iran's Supreme Leader Mojtaba Khamenei responded to the threats with his own warning that if America strikes his country again the response "will expand to an even greater magnitude".

Trump has been politically undermined by the midterms and consequently his negotiating position with Tehran has been weakened.

To strengthen his hand in talks with Iran, America’s Commander-in-Chief may be tempted to dramatically increase air strikes in the Middle East conflict.

The blitz could be a precursor to fresh negotiations to end the conflict.

But if Iran comes under new attack it is likely to lash out at America and its allies in the Middle East and Europe including the UK.

Ahmad Bakhshayesh Ardestani, a member of the Iranian Parliament’s security committee, said European countries would be targeted with missiles if they allow US planes to use their bases to attack his country.

A number of people in London were recently arrested, with two charged, over the alleged “terror plot” against RAF Fairford in Gloucestershire, from where US bombers have been flying to launch “defensive” air strikes against Iran.

Andy Burnham has blamed the incident on Tehran.

A shadowy group reportedly linked to Iran’s hardline Islamic Revolutionary Guard Corps was suspected of being behind a series of arson attacks in the capital earlier this year.

So if the Middle East war escalates, London may find itself the target of retaliation by Tehran.