A decision to build a new hub airport for London rather than expand Heathrow would lead multinational companies to quit the UK in favour of Amsterdam or Paris.

That is the view of a leading business group in the region – the Thames Valley Confederation of British Industry (CBI).

It said multinational companies with bases in the Thames corridor regard access to Heathrow as “vitally important” and a new hub to the east would force some to move abroad.

CBI Thomas Valley director Steve Rankin said: “If a new hub were to move to the east then they [companies] would have to move too.

“But they would move outside the UK, probably to somewhere like Schiphol or Paris or Dusseldorf.”

The Thames Valley CBI is one of five west London business groups to have commissioned a study of the economic impact of relocating London’s hub which they intend to present to the Davies Commission on airport capacity.

Rankin told the Financial Times: “Accessing the UK from a foreign but nearby airport is easy for these [multinational] companies.”

Steve Lamb, chairman of the Thames Valley Berkshire local enterprise partnership, said: “Heathrow is one of the key reasons why the economy to the west of London is as wealthy as it is.”

Unipart corporate affairs director Frank Nigriello told the Financial Times: “To have an airport on the other side of London is not helpful.”

London Mayor Boris Johnson, a leading proponent of an east London hub airport, has argued multinationals would relocate abroad if such an airport is not built.