Allied plans for troop withdrawals from Afghanistan are likely to be discussed when David Cameron greets Pakistani President Asif Ali Zardari for talks at Downing Street.
Mr Zardari's visit to London comes just a week after US President Barack Obama unveiled plans to pull 33,000 American troops out of Afghanistan by next summer, and amid speculation that Mr Cameron may soon announce further reductions in the 9,500-strong UK presence.
The Prime Minister has already announced that 450 UK troops are to come home this summer.
The winding down of the international military presence - due to be completed by the end of 2014 - will jangle nerves in Pakistan both over the possibility of renewed instability in its northern neighbour and the prospect of increased US drone strikes on militants in tribal areas near the border.
In their talks at Number 10, the Prime Minister and President Zardari are expected to discuss security in the border areas, which have long been a haven for Taliban insurgents, as well as the impact on Pakistan's militants of the death in May of Osama bin Laden.
It is the first time the two men have met since the al Qaida terror chief was located and killed by US troops in the Pakistani garrison town of Abbottabad.
The presence of the world's most wanted man in the town known as "Pakistan's Sandhurst" led to strains in the relationship between Islamabad and the West, with widely-voiced suspicions of collusion on the part of elements in the country's security forces.
In his first visit to Pakistan in April, just weeks before bin Laden's death, Mr Cameron said he wanted a "fresh start" in bilateral relations and offered £650 million in education aid and better security cooperation.
The talks come after President Zardari met Foreign Secretary William Hague and Deputy Prime Minister Nick Clegg on Thursday.