MPs and local groups have joined this newspaper in demanding that the London Development Agency (LDA) allows the public to see and comment on its Crystal Palace Park masterplan before it is submitted to Bromley Council.

For many months its consultation website crystalpalacepark.org promised the masterplan would be submitted after the public exhibition of the plans, scheduled for later this month, allowing people to give their views on it to the planners before they finalise the masterplan.

But last week an LDA spokesman told this newspaper that the consultation had closed and that its statement on the website had been a mistake.

Closing down the consultation without any prior warning means thousands of people, who might have been prompted into giving their views by a deadline, have been denied the opportunity.

And the failure to stand by its pledge to allow residents to see and respond to the masterplan before submitting it to the planning authority has been condemned as a major breach of public trust which will seriously undermine the future credibility of the consultation - unless the LDA decides to honour it.

Tessa Jowell, MP for Dulwich and West Norwood, speaking in her capacity as a local MP, agreed. "This issue has for many years been hugely controversial in the area and it is of the utmost importance that local residents have the opportunity to be consulted," she said. "This must be before and in addition to the statutory provisions."

And Beckenham MP Jacqui Lait added: "My view is if the LDA say they are going to do something then they should do. Having made public that they will do it, it doesn't look terribly competent not to."

John Payne, chairman of the Crystal Palace Community Association (CPCA), said the LDA's action: "gives us little faith in their ability to provide the sort of park people want to see".

This week, under pressure, the LDA spokesman said it had made another mistake when it said the consultation had closed, insisting that people will continue to be able to give their views to both the LDA and Bromley Council during the planning process.

And he claimed the statement about the consultation process on the website was "a genuine mistake". He said: "We should have had a closer eye on the copy and we apologise for that."

Although it is true that the LDA has made a series of major gaffes in communication in recent months, it beggars belief that, in a £5million project, the consultation framework on its own website was not approved at the highest level.

The LDA is still refusing to honour its promise to the thousands who have used the website.

But its spokesman could come up with no overriding reason why submission of the masterplan could not be delayed for a few weeks.

He said: "The masterplan is ready now. There are lots of people who are very happy with our consultation. They've had ample chance to engage in the last four years."

He also claimed that the masterplan only sets out the height of landscaping, the size of buildings and issues concerning trees, and that for all the detailed proposals the public will have plenty of opportunity to have their say during the planning process.