Carillion and Serco have signed the definitive business purchase agreement for the transfer of assets.

All that is needed now is approval from Carillion shareholders (as the disposal is a Class 1 transaction for Carillion under the UK Listing Rules) and consent from all the various clients.

The 15 contracts to be acquired by Serco provide facilities management services to NHS sites across the UK, covering five acute hospital trusts and around 20 other public sector organisations.  The portfolio has current annual revenues of approximately £90m.

Assuming that the contracts are all transferred, Serco will pay Carillion £47.7m. Full transition of operations is targeted to be achieved by the end of 2018.

Carillion will lose £1bn from the value of its order book.

Keith Cochrane, Carillion's interim chief executive, said: "I am pleased we have been able to successfully conclude this transaction which will contribute to our efforts to reduce net debt."

Serco chief executive Rupert Soames said: "We look forward to taking on these high-quality, long-term contracts which will add significant scale to our Health business, and will enable us to further improve the quality and efficiency of services we provide to the NHS and our other customers."