Tesco, the country's biggest and most successful supermarket chain, looks poised to win its battle to expand in Abingdon.

But traders fear a bigger Marcham Road store selling more non-food goods will suck the lifeblood out of small, independent shops, putting an already beleaguered town centre under greater pressure.

Tesco's planning application involves demolishing its garden centre and expanding its current 9,275 square metres of floor space to 11,765 square metres - an increase of 2,490 square metres or 27 per-cent. There will be another 200 parking spaces.

The recommendation before next Monday's meeting of the Vale of White Horse District Council's development control committee is that planning permission should be granted.

But if councillors agree to the application it will have to be referred to the deputy Prime Minister John Prescott because it is a departure from the council's Development Plan that favours new shopping in town centres. If Mr Prescott's office is unhappy it would "call in" the application and that could lead to a public inquiry.

Small businesses fear the march of Tesco, squeezing out competition and undermining their future.

Abingdon Chamber president Jill Carver said: "Tesco is an out-of-centre development that is so near to the centre that I cannot believe that it will not be detrimental to town centre vitality. It is like having another town centre shopping area a mile away and with the extra bonus of free parking.

"Tesco should be accessible by a choice of transport including a bus service to and from the town centre but my preference is that plans for an expanded Tesco should not be allowed."

Plans are in the offing to re-vamp the Bury Street shopping precinct. The company that manages the precinct says it has concerns about the Tesco plan but is not objecting.

The Vale council's retail consultants Nathaniel Litchfield and Partners say the Tesco proposal should not harm the retail base of Abingdon town centre.

Flooding is another anxiety but the Environment Agency says it has no concerns providing flood mitigation works are put in place.

Ock Meadow ward councillor Mike Badcock said: "I have concerns about the risk to the Ock Valley flood plain even though the Environment Agency is happy if certain measures are adopted.

"Three years ago much of the car park was flooded. The water came up to the back gardens of some homes in Orpwood Way and people have concerns. There were fears some years ago when plans for a hotel and factory units were proposed but later withdrawn."

The other Ock Meadow Ward councillor and mayor-elect Peter Green said: "I am concerned about the effects a bigger Tesco might have on town centre traders and flooding."

There are worries too about increased traffic likely to be generated by a bigger Tesco store but Oxfordshire County Council believes the proposed extension would "not have a significant impact" on the road network.

The county raises no objection subject to a Section 106 obligation, in which Tesco would contribute nearly £500,000 towards a bus priority lane and cycleway along Drayton Road from the Caldecott roundabout to the bridge.

Three years ago, the store expanded into a Tesco Extra the biggest in Oxfordshire employing more than 600 full and part-time staff. Two years ago the Vale council sold the freehold of the site to Tesco for more than £13m.