document: A 10-year spending plan, published in 2015, added £24.4bn for new maritime patrol aircraft, infantry vehicles, and to speed up the purchase of F35B jets.
  However, a National Audit Office report warned it must first find £5.8bn in new savings to meet the extra commitments.
  Defence minister Harriett Baldwin said it was delivering an affordable plan.
  The government set out its Strategic Defence and Security Review (SDSR) in November 2015, announcing £12bn in extra defence spending.
  The review included plans for nine Boeing P8 maritime patrol aircraft - to replace the RAF's scrapped Nimrod jets - and that the purchase of 24 new F35 fighter aircraft would be accelerated.
  The NAO report said additional planned expenditure amounted to £24.4bn of new commitments to the MoD budget.
  The projected cost of funding the plan increased to £178bn - a rise of 7% - it said.
  4,500 miles (7,200 km) maximum range without refuelling
  490 knots (910km/h; 560mph) maximum speed
  28 P-8A Poseidon aircraft in use by the United States
  2 other countries, India and Australia, have variants of the aircraft in use or on order
  The review said the MoD was already having to use a £10bn contingency fund set aside for emergencies and will have to find another £5.8bn in savings over the next 10 years.
  The report warned the MoD had yet to generate £2.5bn of the £7.1bn savings already factored into the plan.
  However, head of the NAO, Sir Amyas Morse, said the affordability of the equipment plan "is at greater risk than at any time since its inception".
  "It is worrying to see that the costs of the new commitments arising from the review considerably exceed the net increase in funding for the plan.
  "There is little room for unplanned cost growth and the MoD must actively guard against the risk of a return to previous practice where affordability could only be maintained by delaying or reducing the scope of projects."
  The spending plans have also been hit by recent currency fluctuations as the MoD looks to buy new equipment from the US.
  Minister for Defence Procurement Harriett Baldwin said the 10-year plan would deliver "the best kit for our armed forces at the best value for the taxpayer".
  "We are focused on maintaining an affordable programme and delivering the efficiencies we need to reinvest in cutting-edge ships, planes, versatile strike brigades, and greater cyber capabilities, so that our Armed Forces have the equipment they need to keep the UK safe and secure."
summary: The Ministry of Defence will struggle to afford plans to buy new jets, ships and armoured vehicles, the government spending watchdog has warned.