A recording of the alleged call, in which he reportedly advises his party members on tactics, was obtained by Africa Confidential magazine.
He is serving a 50-year sentence for supporting rebels who committed atrocities in Sierra Leone.
The Ministry of Justice said it does not comment on individual cases.
Alain Werner, director of Civitas Maxima, an NGO which builds legal cases against alleged Liberian war criminals, said the allegation was "extremely worrying".
The call, which has been heard by the BBC, is thought to have been made from a landline inside HMP Frankland, near Durham, on 28 January, Taylor's 69th birthday.
In the phone call:
Taylor's supporters put him on their phone's loudspeaker and applause and cheers can be heard as he speaks
He rails against former allies who turned against him and assures supporters that he has never abandoned them
He advises them to avoid people who would betray his party, saying: "Go back to the base and everything will be fine"
He adds: "I'm in a cell but I'm not in prison because my mind cannot be in prison," and describes himself as a "sacrificial lamb"
Africa Confidential also reported that Taylor had been threatening politicians he opposes in other phone calls.
The Residual Special Court for Sierra Leone, the United Nations body which held Taylor's trial, said it was urgently following up with the British government.
Mr Werner, of NGO Civitas Maxima, said: "That he may interfere from his cell in a British jail on the political life in Liberia is extremely worrying, especially considering that there will be presidential elections later this year."
In Liberia's election in October, Taylor's National Patriotic Party (NPP) is in a coalition with the Congress for Democratic Change, which is seeking to elect former football star George Weah, with Taylor's ex-wife Jewel standing as vice-president.