Up to100 British soldiers are being lined up for a mission to train the Nigerian army in its fight against the Islamist extremists of Boko Haram.
Britain has already sent specialists to train troops in Nigeria and deployed three RAF Tornados in the summer as part of the search for 200 schoolgirls who were kidnapped by the rebels.
Military chiefs are now drawing up plans to increase the scale of Britain's support for President Goodluck Jonathan, who is said to be under "enormous pressure" from Boko Haram.
It comes amid speculation that 60 SAS troopers have been sent to fight the Islamic State of Iraq and the Levant (Isil) on the ground. They are said to have been ordered to target high-profile individuals in Iraq such as "Jihadi John", the British terrorist who has beheaded western hostages.
Last week, The Telegraph disclosed that Britain was preparing to send "hundreds" of soldiers into Iraq to train Iraqi and Kurdish forces, accompanied by a military "protection" unit.
The new mission to Nigeria could provide advice on military organisation and technical support. The Nigerian army is said to be poorly run and has been subject to allegations of corruption.
A senior military source said: "We have a small military training mission in Nigeria of only around a dozen. We are thinking of boosting that by maybe up to 100 because the Nigerian Army is making woeful progress against Boko Haram. We have a large Nigerian population in Britain and there is a real fear that if Nigeria falls into chaos it could result in attacks here."
A Whitehall source said plans were being drawn up for providing assistance, and another said the UK was ready to respond positively to requests from President Jonathan for help.