Boris Johnson’s push for the capital to expand further north and swallow up chunks of St Albans and Harpenden has been spurned, with London’s Mayor being warned against making planning changes via the “back door”.

Herts county and St Albans district councils are among 51 local authorities in the wider south east to raise concerns about the Mayor of London looking to neighbouring areas to provide housing to keep pace with growth.

Mr Johnson has recently finished consulting upon the draft Further Alterations to the London Plan (FALP).

And at the end of this month, public consultation on the London Infrastructure Plan 2050 (LIP) will close.

But local councils are calling upon Mr Johnson to publicly commit to provide for future housing needs within the capital’s boundaries, and state that the wider south east will not be encroached upon to cater for any shortfall.

The London Plan says that 49,000 additional homes a year will need to be built over the next decade.

During the consultation, letters were exchanged between Bedford borough council and the Greater London Authority (GLA), in which the latter suggested that the wider south east should be prepared to cater for any failure of London to provide for the predicted level of need.

This prompted 51 authorities – dubbed the “Bedford 51” – to band together and tell the GLA to amend the plan.

In a recent report to a Herts county council’s planning panel, officers said meeting London’s housing need, “cannot be allowed to happen in a piecemeal and ad hoc fashion by the back door, brought on by delivery failure in London”.

Both plans are causing concern, with the county council warning there are implications for Herts.

In setting out where future Londoners might live, the LIP has set out four potential growth scenarios.

One of these sees the wider south-east providing for an extra one million people.

And major growth to the north of London appears to include St Albans, Hemel Hempstead, Watford, Hatfield, Broxbourne. Waltham Cross,Hoddesdon, Cheshunt and an area to the west of Stevenage stretching from Hitchin down to Harpenden.

But Mr Johnson’s expansion bid has angered county councillor for The Colneys Dreda Gordon, who said she was disappointed in his proposal to encroach upon the St Albans district.

Cllr Gordon said that local planning officers have told her that this district’s housing need, projected to be 436 homes a year, would not include London’s shortfall.

She added: “We are under pressure to deliver our own housing requirements. And we are shortly going out to consultation on our Strategic Local Plan, so I don’t think residents will be happy to accommodate London’s shortfall.”

The London Infrastructure Plan says that it has identified 33 tracts of brownfield land with “significant capacity” for new homes and other developments, but there was “also capacity within surrounding areas to increase densities.”