British Prime Minister Boris Johnson will seek to recall parliament next week from its summer break over the developing crisis in Afghanistan, domestic media reported on Sunday.
MPs are likely to be called back for urgent debate on what Britain, which lost 457 troops in the two-decade long war, should do next, Downing Street sources told Sky News and the Press Association.
Taliban fighters were on the outskirts of Kabul on Sunday and on the brink of a complete military takeover of Afghanistan, leading to British politicians to call for a last-ditch intervention.
Conservative MP Tobias Ellwood, chairman of the Commons Defence Committee, urged Johnson to "think again" about stepping in.
"We have an ever-shrinking window of opportunity to recognise where this country is going as a failed state," he told Times Radio.
"Just because the Americans won't, does not mean to say that we should be tied to the thinking, the political judgment -- particularly when it is so wrong -- of our closest security ally.
"We could prevent this, otherwise history will judge us very, very harshly in not stepping in," he warned.
Ellwood said the government could deploy the Royal Navy's HMS Queen Elizabeth carrier strike group to provide air support.
He called the crisis "the biggest single policy disaster since Suez".
- 'Deeply shocking' -
Johnson vowed on Friday that Britain will not "turn our backs" on Afghanistan, even as he confirmed the imminent withdrawal of most embassy staff in the face of a rapid Taliban onslaught.
However, he said that those calling for an intervention "have got to be realistic about the power of the UK or any power to impose a military solution -- a combat solution -- in Afghanistan."
With the Islamists seizing control of more Afghan cities, Britain is deploying around 600 troops to help evacuate its roughly 3,000 nationals from the country, and Johnson said the "vast bulk" of remaining embassy staff in Kabul would return to the UK.
Opposition Labour leader Keir Starmer backed calls for the recall of parliament, saying in a statement: "The situation in Afghanistan is deeply shocking and seems to be worsening by the hour.
"The government has been silent while Afghanistan collapses, which let's be clear will have ramifications for us here in the UK.
"We need parliament recalled so the government can update MPs on how it plans to work with allies to avoid a humanitarian crisis and a return to the days of Afghanistan being a base for extremists."
Most of the remaining British troops assigned to the NATO mission in Afghanistan left last month, according to Johnson.
As well as the fallen troops, the conflict has cost Britain around £40 billion ($55 billion, 46.7 billion euros).
In 2014, the British mission in Afghanistan, centred around the restive southern province of Helmand, shifted from a combat operation to one focused on supporting Afghan national forces, with the help of around 750 troops.