The Yorkshire Bank is to shut 40 branches over the next 18 months as part of a dramatic cost-cutting programme initiated by its Australian owner, it was confirmed today.

National Australia Bank (NAB) said it was axing the Yorkshire branches along with 60 sites at its Glasgow-based Clydesdale Bank, as it outlined plans to cut 4,200 jobs from its global operations following its half-year financial results.

NAB has not yet confirmed which of its branches - which includes a network of more than 20 across the Bradford district - are to go.

The bank had already announced in March that up to 1,700 jobs were to be axed as it looked to save about £117 million a year at the businesses.

NAB chief executive John Stewart said today the closures were "in response to the changing needs of our customers, which has meant some branches are no longer viable."

He added: "Our research has shown that in any one month 75 per cent of our customers do not use a branch at all, and 11 per cent use a branch only once. This is about providing our customers with the appropriate network for their needs."

Clydesdale was founded in 1838 and has 217 branches, while the Yorkshire, which has its headquarters in Leeds, dates back to 1859 and has 232 sites.

The Australian bank acquired both businesses in the late 1980s.

NAB carried out a review of its UK arm after offloading its Irish business - Northern and National Irish Bank - earlier this year.

The bank aims to invest heavily in 50 "flagship" branches in key centres, sparking fears the cuts will be made in rural areas and smaller communities.

It said it would increase its number of regional "financial solutions centres", similar to that which it opened in Canal Road, Bradford, last year and which serves the whole of West Yorkshire.

Today Mary Alexander, national officer of the Amicus union, said: "This is a serious blow for the bank's customers, particularly in some remote areas. The bank has reneged on its promise not to close the 'last branch in town' in several communities.

"We will continue to put pressure on NAB to review this drastic programme of cuts and to ensure that staff affected are treated fairly."

The union said it would fight any compulsory job losses.

The Yorkshire Bank has a vast branch network across the district, including sites in: Bradford city centre, Great Horton, Idle, Laisterdyke, Toller Lane, West Bowling, Cleckheaton, Cross Hills, Guiseley, Ilkley, Keighley, Otley, Queensbury, Shipley, Skipton, Pudsey, Horsforth, Yeadon, Heckmondwike and Brighouse.

As reported in later editions of yesterday's Telegraph & Argus, Abbey National has said it now plans to cut 1,000 more jobs than the 3,000 it had previously had announced. The bank, which laid-off 76 staff in Bradford last month, said it did not yet know where the cuts would fall.