Flexibility, a BMW manager in Munich told me when the company was first proposing to buy the Rover works in Cowley in 1994 from British Aerospace, is the name of the game in the car industry.

The business is as seasonal as farming, with most customers buying new cars in spring and summer and so a manufacturer must be able to adjust its production accordingly — which means retaining the ability to increase or decrease the workforce as demand dictates.

When the German bosses proposed to buy Rover, they made it clear to the British workers that they should vote for the Working Time Account — or BMW would simply not go ahead with the purchase.

Put simply, the Working Time Account enables workers — “associates” as BMW prefers to call them — to take time off when demand is low, but for the company to demand that they pay back the time with extra work when demand is high.

In addition, from the start, BMW employed fluctuating numbers of agency workers to achieve maximum flexibility. Now, with the Agency Workers Regulations 2010 due to come into force on October 1, 2011, the company, along with many other large Oxfordshire employers, may be forced to look again at these arrangements. For instance, only last month BMW confirmed that it was axing the Saturday shift and therefore gradually laying off 140 people. A spokesman for BMW, Rebecca Baxter, would only say: “The company continues to monitor the progress of the Agency Workers’ Directive to understand what this means for the business.”

The fact is that hirers and agencies will now have to look more carefully at their agreements. Agencies, in particular, may be forced to rethink whether they can go on offering temporary staff the same terms.

Judith Thompson, a spokesman for Right4Staff, which supplies agency staff to BMW in Cowley, said: “The Agency Workers Directive comes into force in October 2011. However, the comprehensive guidance from the Government is yet to be published. Once the legislation has been clarified we will be meeting all our clients to discuss how the directive may impact on them.”

Employment law expert Craig Gordon, of Abingdon employment advisers www.HRbullets.co.uk, said: “Hirers of agency workers should not panic. The main burden of compliance will fall on staffing companies but hirers will have obligations towards agency workers from day one of any assignment.” Employers should identify which workers will be covered by the new law and get together with their staffing companies to discuss how they are going to handle things, he said.

He advised employers: “Bear in mind that staffing companies may well seek to pass on their increased costs to you as the hirer. They will certainly be asking you for detailed information about your working and employment conditions in preparation for the new rules taking effect.”

But asked whether BMW, under the new regulations, would be able to repeat its now famous act at the start of the financial crisis in 2007 — when it suddenly gave 800 agency workers, some of whom had worked at the plant for several years, their marching orders — Mr Craig said: “Yes.” While the regulations improve the lot of agency workers, they do not change their status.

“From day one, for instance, they will be entitled to benefits such as canteen, childcare and transport. But the use of agency workers will still enable hirers to achieve flexibility in the workplace. They remain the employees of the agency.”

However, hirers will inevitably find that maintaining flexibility becomes more expensive, thanks to the agencies’ increased costs in offering their staff better deals.

Nor is it only manufacturers like BMW who will find themselves affected by the new regulations. Tracy Hoodless, of Oxford employment agency Champion Recruitment, said: “If an organisation is supervising, controlling and directing someone, then, after 12 weeks, that person has the right to equal treatment to the comparator — a staff member of that organisation doing a comparable job.”

She added: “With the spending cuts in the public sector, temps are already finding themselves to be the first out of the door. We only hope that next year they will be back in demand.”

Over at the Radcliffe Hospital Trust that hope appears forlorn.

Spokesman Oliver Francis said: “We are cutting back on agency staff. And as regards the new regulations, it will be the agencies, not the hirers, who will have to pay the extra benefits to staff remaining in post for more than 12 weeks.”

Employment lawyer Rebecca Ireland, of Oxford law firm Morgan Cole, explained what benefits the new regulations will bring temps after 12 weeks.

She said: “They will be entitled to basic working conditions which are no less favourable than if they had been recruited directly by the hirer. However, occupational pensions and sick-pay schemes are specifically excluded. Employers cannot avoid these rights simply by terminating and immediately re-engaging at 11 weeks, as continuity will only be broken if there is a gap of at least six calendar weeks between assignments.” The exception is if the agency worker starts a new assignment with the same hirer but the work is “substantively different”, said Ms Ireland.

But will the regulations mean harder times ahead for young free-wheeling temps, many of whom like nothing better than to dodge in and out of jobs? Will they find the supply of those jobs drying up? No one knows.

But Mr Gordon said: “I think the Government has got it about right. However, it costs nothing for an agency employee to start proceedings in an Employment Tribunal against an employer.”

Ms Hoodless added: “One interesting point in all this is that it doesn’t work the other way round. If, after 12 weeks an agency worker finds themselves better off than a comparator — a staff member at his or her place of work — the employer may not drop his or her benefits downwards.”