VAUXHALL has replaced all jacks in a union's car fleet following safety fears - but not those of thousands of ordinary members of the public who own the same model, the Vectra.

Last night, the company indicated it was unlikely to reconsider that position, although acknowledging the design of the jack had been changed since the original safety alert.

A spokesman insisted the old-style jacks ''will not fail'', provided instructions in the owner's handbook were followed.

However, a lawyer expert in liability claims argued Vauxhall should institute a total recall rather than face even a ''potential risk'' of having an injury on its conscience, let alone legal action.

Solicitor Paul Santoni said he was astonished the firm had not instigated a recall programme, and added: ''At the very least, it must be able to identify the batch which included the faulty jack and substitute them.''

Vauxhall confirmed it had replaced jacks - free of charge - in up to 40 Vectras used by staff employed by Unison, the health union. That followed an incident in which a jack had ''failed'', with the union officer narrrowly escaping being hurt in what Unison dubbed ''a near miss'' in health and safety terms.

The car manufacturer declered that, ''in the interests of all concerned'', the material specification of future jacks would be changed.

However, the alteration affects only newly produced cars - with owners of earlier Vectras, unlike the Unison staff, not being given replacements.

Vauxhall told the union it had been unable to produce the same effect on others under laboratory test conditions. That failed to satisfy Unison, which continued to advise staff not to use the supplied model and instead summon the Automobile Association to roadside emergencies.

Vauxhall subsequently agreed it would replace the jacks. In one letter to Unison, its retail support centre said an analysis of the failed jack had indicated the component was structurally sound - but had failed on side lifting.

The letter added: ''We have in view of this failure carried out thorough testing to a number of similar vehicle jacks.

''Although we could not replicate the failure nor condemn the integrity of the part, in order to obviate any possible recurrence of the condition, and in the interests of all concerned, we have changed the material specification of the jacks' lifting jaws.''

Mr Ian Smith, Unison's national health and safety officer, said yesterday: ''We were delighted with that outcome, which followed a near miss. We had to look at the worst possible outcome in health and safety terms: that someone could have been crushed.''

He said the union, on receiving replacements, had not pursued the matter further but acknowledged there could well be wider public concerns in light of what had happened to one of its Vectra users.

A Vauxhall spokesman said the replacements were a gesture of goodwill to a fleet customer and stressed: ''We have yet to hear of a case when a jack has failed when used in accordance with manufacturer's instructions.'' He described the new design as part of an ongoing improvement process.

Lawyer Paul Sanotini, who is representing many victims of the world's worst E-coli outbreak in Lanarkshire, said he believed Vauxhall should replace all the jacks.

He considered Vectra customers would have strong cases should the failure be repeated because a potential defect had been uncovered, albeit in only one piece of equipment.

Mr Santoni said: ''It is clear that problem could be avoided by a vehicle recall, a common practice within the car industry. It is also clear the probability of harm is high when a jack collapses.''