According to a series of defence planning assumptions, the UK will in future be able to carry out a one-off intervention, such as an invasion of another country, with no more than 30,000 troops. This is about two-thirds the size of the force of 45,000 British troops which went into Iraq in 2003.

The assumptions also state that Britain will be able to deploy no more than 6,500 troops with maritime and air support in a long-term stabilisation force. This is well below the figure of 10,000 troops which are currently deployed on long-term stabilisation in Afghanistan, mainly in Helmand province.