COUNCILS in Oxfordshire claim undercover surveillance is an important weapon in the fight against fraudsters.

New figures show authorities are secretly targeting pubs and off-licences serving underage drinkers, as well as the suspected sale of illegal fireworks and rogue traders.

Between April 1, 2008 and March 31 this year, Oxfordshire County Council used surveillance 192 times – the fourth highest figure in Britain.

County authorities said they only authorised operations as a last resort.

The council could not say how many successful prosecutions resulted.

Ian Marriott, group manager for Oxfordshire’s Trading Standards team, said: “Our service carries out directed surveillance on a regular basis.

“Each time a surveillance operation is planned, it must be approved by a senior officer.

“This is to make sure the surveillance is necessary, proportionate and does not intrude on others.

“The great majority of approvals are for test purchasing, to check if shops are illegally selling alcohol, tobacco or knives to children.

“The council takes underage sales of these items, particularly knives, very seriously and we make no apology for using surveillance for this purpose.

“It is the only way that trading standards can obtain evidence.”

It does not carry out surveillance on parents checking if they live in a school’s catchment area.

Oxford City Council ordered 12 operations in two years, all against benefit fraud.

City spokesman Fiona Colcutt said: “We ensure that the use of surveillance is reasonable, necessary and proportionate to carry out this as part of our investigation process.”

Describing its use as “a last resort” she added: “Use of surveillance is only undertaken once a risk assessment has taken place to ensure that there is minimal collateral intrusion on others.”

West Oxfordshire used the powers 29 times, Vale of White Horse 26 times, Cherwell four times and South Oxfordshire twice.

The figures, from a Freedom of Information request by campaign group Big Brother Watch, come days after the new coalition Government vowed to ban the powers unless they were authorised by a magistrate or used to stop “serious crime”.

Last July the Oxford Mail revealed that almost 40 per cent of shops targeted by an undercover Trading Standards’ sting sold knives to a 14-year-old child.

The research revealed that nationally 372 councils authorised 8,575 surveillance operations in two years.

Big Brother Watch, which was formed by the people behind the TaxPayers’ Alliance, wants local councils to be stripped of all surveillance powers.