SAS units threatened by new defence cuts In last year's Autumn Statement, Mr Osborne announced plans to cut an extra £700 million from the defence budget by April 2015, on top of deep cuts announced in 2010. Those cuts could be carried over into the next spending round, reducing the "baseline" from which the defence budget will be calculated in the second half of this decade. Whitehall sources say defence chiefs fear that rolling over the latest cuts into the years after 2015 could force them to tear up the 10-year plan for the Armed Forces set out in the Strategic Defence and Security Review in 2010. Sources said reopening the review would raise the prospect of reductions in military capabilities, including special forces and the amphibious warfare operations of the Royal Marines. The precise numbers of special forces troops are a secret. Even after expansions in recent years, they are believed to number around 1,000, with as many as 600 specialist support troops. Personnel from the Special Air Service, Special Boat Service, the Special Reconnaissance Regiment and the Special Forces Support Regiment are currently deployed on operations around the world, in countries including Afghanistan and Mali. They also play a major role in domestic counter-terrorism operations. Special forces units recruit from all three Armed Forces, but mostly from the Army. The Coalition's current defence cuts are reducing Army manpower from 102,000 to about 80,000. In 2011, the head of the infantry warned that the SAS was struggling to recruit enough high-quality entrants because troops did not have time to train properly for its gruelling selection process. In a letter leaked The Telegraph, Brigadier Richard Dennis said that action was needed to improve the "depth and quality" of potential special forces recruits. Now, a well-placed defence source suggested that further cuts in the Armed Forces would make it harder for Britain to generate and maintain top-quality special forces on their current scale. "Generating significant elite forces is difficult enough at the best of times, and if we get hit again, it is only going to get harder for us," said the source. That is something that the Treasury might bear in mind. Another source confirmed that additional cuts after 2015 could shrink the Armed Forces even further. "We can absorb the latest cuts without looking at personnel, but if they are carried over into the baseline [for the next spending round], then we are looking at much bigger cuts and those questions would be opened up again," said the source. The warnings will add to the pressure on Mr Cameron and Mr Osborne over the future defence budget. Gen Sir David Richards, the Chief of the Defence Staff, warned last month that the Autumn Statement would have "further implications" for defence after the current four-year spending round. Philip Hammond, the Defence Secretary, is also said to have questioned Mr Osborne over the justification for more defence cuts. The strategic review cut the budget by 8 per cent over four years, to £33.5 billion in 2014-15, but Mr Cameron promised "year-on-year real-terms growth in the defence budget in the years beyond 2015." The MoD has based its spending plans on an assumption that the promise will be honoured. The department said yesterday that ministers would fight "vigorously" for funding in order to deliver the special forces capability set out in the defence review. "The UK will continue to have formidable fighting forces, backed by the fourth biggest defence budget in the world," said a spokesman. The SDSR made clear that we will maintain the capability of our special forces and we have invested more in them to increase their effectiveness. The budget for 2015-16 will be determined in the current spending review and we will vigorously make the case for funding to support the delivery of Future Force 2020. Mr Cameron's visit to Algeria will be the first by a Prime Minister since its independence 51 years ago. On Thursday, he will attend an international development conference in Liberia.