A P-8 Poseidon aircraft at RAF Lossiemouth. Nine of the aircraft are due to operate from the base by 2020

The weak pound has driven up the price of Ministry of Defence spy planes by £155 million, The Times can reveal.

Nine P-8 Poseidon aircraft are due to operate from RAF Lossiemouth in Moray by 2020 after being manufactured in the United States by Boeing under a contract agreed in dollars.

They are part of the MoD’s ten-year defence equipment programme, which the National Audit Office (NAO) last month said was facing a funding gap of between £7 billion and £15 billion.

Stuart Andrew, the minister for defence procurement, confirmed the cost changes in a letter to the chief librarian of the House of Commons library.

Savings of £52 million have been made to the Poseidon programme, according to the note. Mr Andrew previously told