An ambitious theme park project billed as 'Kent's answer to Disneyland' has been given a final deadline to submit its bid for review.

Large parcels of land on the Swanscombe Peninsula have been earmarked by developers for the £2.5 billion London Resort proposals.

The project, set on a 535-acre marshland and brownfield site between Dartford and Gravesend, was first announced in 2012 with a view to opening in 2019.

But the prospective park has been fraught with delays and an official examination is yet to get under way.

Initial delays were granted at the request of the developers to address outstanding concerns, including the area's new found status as a site of special scientific interest (SSSI).

Theme park bosses had hoped to delay the start of the review until June/July but the Planning Inspectorate – the body tasked with deciding the bid – has now set new "strictly-timed" deadlines.

London Resort Company Holdings (LRCH), the company behind the scheme, has now been told to submit its final bid for examination by March 15.

This includes work to address the SSSI status, updated documents on transport and traffic and a full list of engagements.

It comes after growing pressure from the examining authority to justify continuing delays and a "lack of progress".

Criticisms have been repeatedly levelled at the developers for missed deadlines and it has been accused of "failing to engage" with local authorities and businesses.

In his latest letter published to the Planning Inspectorate portal, lead member Rynd Smith said it appeared that "effective engagement" had all but but ceased.

"This general lack of progress appears to have affected a broad range of matters, issues and questions relevant to the Examination, not just the question of the SSSI designation," he said.

"Its scope is such that there must now be very considerable doubt as to whether important and relevant matters bearing substantially on traffic, transport, shipping, ports, water utilities and the natural environment (amongst other matters) can feasibly be addressed in a timescale to an examination commencing in July 2022."

He went on to add that an enduring delay to the project could lead to substantial harm to affected parties.

This includes companies subject to controversial compulsory purchase powers on the surrounding business estates who claim the development has "paralysed" their futures since it was first announced and likened it to "being on death row".

In these circumstances, the Planning Inspectorate said a decision had been made in the interests of resolving "enduring uncertainty".

A virtual meeting has been earmarked for March 29 to consider "draft proposals" for examination.

It will then be decided whether or not examination will go ahead there and then, or a deferred timescale based on the requested evidence.

Dartford MP Gareth Johnson welcomed the decision as "sensible" and said it was time to bring the "whole saga" to a conclusion.

He said: "This project has been under consideration for the best part of a decade and this uncertainty for local businesses and residents cannot continue.

"It has always been the case that this proposed development raised concerns over its impact on traffic and the local environment.

"There has been more than sufficient time to consider the merits of having a theme park on our doorstep and it is time to bring this whole process to a conclusion."

Environmental campaigners have raised more than £50,000 to protect the Swanscombe Peninsula and cover legal bills to fight against the development proposals.

If given the green light the London Resort would be one of Europe's largest leisure and hospitality attractions with more than 100 hectares of marshland – equivalent to 140 football pitches – set aside for rides, hotels, bars and other event spaces.

LRCH chief executive PY Gerbeau, the man who masterminded the 02 project in Greenwich, had requested more time to further hone the bid.

The French entrepreneur pointed to the role the project could play in the government's Build Back Better programme, its connection to the Thames Estuary growth plans and its forecast of £50bn economic growth by 2039.

Mr Gerbeau added in his previous response to the Planning Inspectorate that a decision to proceed to examination with an incomplete bid would be "deeply unfortunate".

A spokesman for The London Resort said: “We are looking forward to the preliminary meeting in March and to bringing the first next-generation theme park to the UK."