They will offer wide expertise in a number of areas, ranging from cyber warfare to chemical attacks.

The unit will spearhead Operation Temperer, the Government’s over- arching security plan to provide thou- sands of soldiers to protect civilians during a high terror threat.

It follows warnings by intelligence chiefs at the Joint Terrorist Analysis Centre that extremists are now seeking new targets and “spectacular incidents”, including ports and power stations.

The routing of Isis from its so-called caliphate in Iraq and Syria has seen hundreds of well-trained jihadis make their way through Turkey, determined to wreak havoc in Europe.

Operation Temperer, first used after the Manchester Arena attack, is already geared up to deploy more than 5,000 soldiers, including up to 100 Special Forces troops drawn from the SAS, SBS and the Special Forces Support Group.

They would support police and counter-terror agencies in the event of a terror attack.

Specialists in the new nucleus will include chemical experts from the Royal Tank Corps, bomb disposal officers from the Royal Logistic Corps, combat surgeons from the Royal Army Medical Corps and Royal Navy, search engineers from the Royal engineers to detect boobytraps and cyber warfare personnel from the Royal Signals.

Military chiefs are also reviewing the concept of a “rapid response medical unit” of doctors and nurses, who would use their specialist skills in treating chemical injuries.

Although they will undergo a tough selection process, they will not offi- cially become part of the SAS or SBS.

Potential terror threats also include maritime targets around Britain’s coastline, particularly oil tankers, chemical strikes at public events and a growing threat of drone-led attacks.

Sources confirmed the new unit, which will be flown by Chinook or Augusta helicopter, would be “on operational support every day”.

Training has already started. In December volunteers joining the unit as medics underwent an intensive two-week course in south Wales, called exercise Black Serpent, in which they were required to deal with an attack on a football stadium, a multiple suicide assault in a shopping centre and an attack on London’s Underground.

This month others rehearsed a hos- tage scenario at a disused school in Almondsbury, South Gloucestershire.

Last night a senior source said the new task force was designed to bring a team of specialists together to focus on a set of skills in order to deal more quickly with almost any threat.

“Operational demands on Special Forces have never been higher,” said the source. “We are deployed globally and while we have specialists they are already on active duty.”