Patients in west Hertfordshire may have to wait until 2028 for a new hospital on the site of Watford General, it has emerged.

Bosses at the West Hertfordshire Hospitals Trust have drawn up plans for the new hospital, as part of plans to retain and redevelop three existing sites in Watford, St Albans and Hemel Hempstead.

They had initially hoped that work could start at the Watford site next year (2022) – with the work complete as early as 2025.

But despite a promise of funds by Prime Minister Boris Johnson, during a visit to the hospital in October 2019, the trust is yet to be allocated funding from the Treasury.

And now latest information to emerge from the trust suggests that construction at the site may not even start until September 2024.

The trust’s bid is currently being considered as part of the government’s £3.7billion New Hospital Programme.

The programme aims to deliver 48 ‘new’ hospitals by 2030, including a number of "pathfinder£ bids, of which West Herts is one.

In its latest briefing to stakeholders – seen by the Local Democracy Reporter Service (LDRS) – the trust reports the programme "window for construction" for pathfinder trusts runs from April 2023 to September 2024.

And the LDRS has now learned the programme currently anticipate that construction will be complete at the most developed pathfinder schemes between 2026 and 2028.

According to the trust’s update to stakeholders, the trust is continuing to work on the outline business case for the development, which it hopes to complete next year.

A few weeks ago, the Department for Health and Social Care wrote to trusts, including West Hertfordshire, informing them they needed to submit redevelopment schemes capped at £400million, alongside the trusts' preferred and more costly options.

Related: Council backs 17-storey Watford General Hospital plans

Related: West Herts NHS Trust in battle for extra cash for redevelopment

Commenting on the current timescale, a spokesperson for the West Herts Hospitals Trust told the LDRS: "We are really pleased to be a part of the New Hospital Programme and we are continuing to work hard so we can open new facilities for patients in west Hertfordshire as soon as possible.

"We are confident that the work taking place at a national level to secure contractors and to provide a standardised approach to design will be of benefit to us and the hospitals who follow on after us."

Once the business case is complete it will be scrutinised by officials from the New Hospital Programme – before a funding decision is made by the Treasury.

Commenting on the timescale of the New Hospital Programme, a Department of Health and Social Care spokesperson said: "We remain on track to build 40 new hospitals by 2030, backed by an initial £3.7 billion, which will provide better care for patients, an improved working environment for staff and help the NHS reach its net zero carbon ambition.

"We are working closely with all NHS Trusts within the programme, including West Herts Hospital, to plan how and when new hospitals will be built across the decade and timescales for individual schemes may change as the programme progresses."