Now even the Afghan president is poking fun at Gordon Brown's leadership troubles

On a whistle-stop tour to meet British troops, the Prime Minister held talks with Hamid Karzai, in the capital Kabul.

Although Mr Brown praised troops as 'true heroes' and pledged £120million more in aid, journalists repeatedly asked whether his position was under threat from Foreign Secretary David Miliband, following recent speculation in Westminster.

Afghanistan's President Hamid Karzai walks with Prime Minister Gordon Brown at the presidential palace in Kabul

Noticing Mr Brown's plight, President Karzai stepped in. 'Cabinet ministers plotting is nothing new,' he joked. 'We have it in Afghanistan – although not my Foreign Minister.'

Mr Brown looked irritated by the intervention and the persistent questions.

He insisted: 'It is a good relationship. We get on with the job.'

The Prime Minister made the 90-minute stopover at Camp Bastion, where UK forces are based, en route to the Olympic Games in Beijing.

He told troops they had displayed 'the same courage, professionalism and dedication' as the competitors in China.

Addressing about 300 troops from 16 Air Assault Brigade, he said the nation owes them a 'huge debt of gratitude' for fighting the Taliban.

'This week we are celebrating the Olympics where we have had great success,' he added.

'But this week also I believe that our Olympic athletes and everybody else in our country will remember that you have showed exactly the same courage, professionalism and dedication. 

'You make our country proud every day of the week and every week of the year. You are truly the heroes of our country. You know that you are in the front line in the fight against the Taliban.

'You know that by what you are doing here, you prevent terrorism coming to the streets of Britain.'

No.10 aides insisted however that Mr Hu's comments had not been intended as a barbed reference to the torch's reception in London and that the 'atmospherics' between the two men had been very good.

Mr Brown, who praised the 'spectacular' success of the Beijing Games, said that he had made clear that he hoped the greater openness which the Olympics had brought would not end once the Games were over.

'It is in China's interest. It would be a very important gesture to the rest of the world if they were to say that these restrictions could be permanently removed,' he told reporters.

Mr Brown said that he also urged the Chinese to pursue their talks with representatives of the Dalai Lama of greater autonomy for Tibet to a 'productive' conclusion when discussions re-open in the autumn.

'I think there is more common ground between the Chinese authorities and Tibet than is sometimes realised,' he said.

The Prime Minister also tackled Mr Hu over China's stance on Zimbabwe and Darfur, where it has been criticised for supporting repressive regimes.

'He responded by saying that these are issues that will be part of our continuing discussions,' Mr Brown said.