Heathrow has been dismissed as “huge but inadequate” by a senior aide to London Mayor Boris Johnson, who called for the airport to be closed.

The Mayor’s aviation advisor Daniel Moylan suggested Heathrow could be redeveloped as “a whole new London borough with 200,000 people”.

Moylan told the Advantage conference in Malaga: “Heathrow is the size of a London borough, but only half the size of Paris Charles de Gaulle airport. It is huge and inadequate.

“It is a moral scandal that we designate the whole area to this one noise-polluting activity. It is perfectly possible to use the site in a way that is socially responsible and of no cost to the taxpayer.”

Referring to the Commons Transport Select Committee report on aviation strategy published today, Moylan said:

“The report says we should invest in Heathrow rather than a new site.”

He dismissed that, arguing: “Building on Heathrow is not practical. Anyone who says [expanding] Heathrow is a quick fix knows it’s not true.

“It would require five years of planning, five years to implement and be full before you could open it.

“It would be hugely expensive and we would still be left with the huge and growing problem of noise affecting hundreds of thousands of Londoners.”

However, Moylan said: “The report does make clear we must have a hub airport in the southeast and it must be capable of having four runways and be pretty unrestrained, allowing night flights.

“There are only really two options – to build on Heathrow or build a new airport and close Heathrow.”

He said: “So many people argue we can take existing airports, add a runway at Gatwick, a runway at Stansted or send passengers to Manchester or Newquay.

“I don’t blame Gatwick for arguing its corner, but it’s a load of nonsense.

“The Mayor is pretty open to where a new airport might be. Boris would be perfectly happy with a four-runway Stansted. Personally, I favour an estuary airport.”

Moylan conceded: “The real problem [with an estuary airport] is the birds – whether legally you can move them and whether it is technically possible.”

Accused of taking an “elitist view” that dimished the importance of regional airports, Moylan said: “Regional airports have a useful role, but are not the same as a hub airport. They mainly feed a hub airport.

“It is nothing elitist to say ‘London needs a hub airport’. It has one, but it’s not very good.”

In an aside, Moylan told the conference: “Being invited to Malaga is the most exciting thing to happen to me since I started working for Boris.”