The planned merger of Heatherwood and Wexham Park Hospitals and Frimley Park Hospital foundation trusts has been delayed due to “legal, financial and other practical challenges”.

The merger was meant to complete by 1 August, but a spokesman for Frimley Park said that while “substantial progress” had been made, more time was needed to “work through the raft of outstanding legal, financial and practical challenges”.

He did not give a revised deadline, but said the “parties involved” were committed to bringing the “process to the quickest possible conclusion”.

Wexham Park Hospital

There is no new date for the merger of Heatherwood and Wexham Park Hospitals (pictured) and Frimley Park Hospital

The announcement came as clinical commissioning groups in the area revealed they were in discussions with NHS England about what financial contribution commissioners would have to make to the “transition costs” of the merger.

HSJ understands the CCGs did not initially expect to have to contribute to the merger costs.

The latest finance report for Windsor Ascot and Maidenhead CCG highlighted a risk that the group “has to contribute to transition and/or integration costs associated with the proposed acquisition of Heatherwood and Wexham Park Foundation Trust by Frimley Park Foundation Trust”. It added: “[This] risk, which is very high, is being actively discussed with the NHS England Area Team.”

A spokeswoman for Surrey Heath CCG, when asked by HSJ how much the group expected to contribute to the merger, said there was “no formal guidance so we are in discussion with all relevant parties over who is responsible”.

Several of Heatherwood and Wexham Park’s commissioners are among the most underfunded in the country, including Windsor, Ascot and Maidenhead, Slough, and Bracknell and Ascot.

Frimley Park has also delayed signing its contracts with Surrey Heath and North East Hampshire and Farnham CCGs.

North East Hampshire board papers said: “Frimley Park Hospital are declining to sign the contract on the advice of their solicitors pending the transaction with Heatherwood and Wexham Park Foundation Trust”. They added that the CCG is “applying pressure” to the trust to sign the contract.

The Frimley Park spokesman said: “We had been holding off signing the contract in case any of the details of the potential acquisition need to be added into it. We have been making good progress to resolve the issue.”

Matthew Tait, Thames Valley area director for NHS England, said: “NHS England and CCGs have been asked to contribute towards integration costs, but at this stage, final figures have not yet been determined.”

Frimley Park will not be contributing to the transition costs of the merger.