President Pervez Musharraf has said that Pakistan's success in fighting terrorism is critical and any failure could impact on the West.
Mr Musharraf denied Pakistan was involved in any "double-crossing"
In an address to a British think tank, he called for support and encouragement not "criticisms and insinuations".
He outlined his strategy for defeating al-Qaeda and the Taleban, and securing Pakistan's border with Afghanistan.
The president reiterated that delayed elections now due next month would be "free, fair, transparent and peaceful".
In his speech to the Royal United Services Institute (RUSI) in London, he said: "I would ask anyone to give me how [the polls] can be rigged, and if anyone gives me any suggestion, I would be too glad to pass it onto the chief election commissioner for implementation."
Parliamentary polls planned for January were postponed until 18 February after the opposition leader, Benazir Bhutto, was assassinated at a campaign rally.
The president insisted that his country was capable of carrying out a full investigation into her death.
He said that the assistance of detectives from the UK had been requested because "there may be some weaknesses in our forensic capabilities, in our technical capabilities".
Streets of Europe
The focus of Mr Musharraf's address, which comes on the first day of a three-day visit to Britain, was on the challenges of fighting terrorism.
"We are in the forefront fighting terrorism and extremism, our success is critical. We have to win because if we lose I think it will have an impact on the region and the world, maybe in the streets of Europe.
"So therefore we have to be together and we have to reinforce each other, encourage each other, support each other, instead of criticising and insinuating," he said.
Pakistan has a number of nuclear-capable missiles
The president said his strategy in the so-called War on Terror was "multi-pronged" - military, political and socio-economic.
He denied that Pakistan was involved in any "double-crossing", insisting: "We are not doing this for anyone, we are doing this for ourselves, for Pakistan. And I believe that."
The president said that the only way for militants to gain access to Pakistan's nuclear arsenal would be if al-Qaeda or the Taleban overthrew the army or if extremist religious groups won next month's elections.
Mr Musharraf, whose UK stop is part of a European tour, is expected to meet Prime Minister Gordon Brown, and address business leaders and members of the Pakistani community.
The majority of Britain's estimated 1.6 million Muslims are of Pakistani descent.