It's a cautionary tale with a happy ending, told by Nic Barnard
You would think supply teaching brought enough hazards: the unpredictability, bored youths asking when they're getting a "real" teacher, the wrath descending when you use the wrong mug in the staffroom.
Worst of all, it can be perilous to the pocket: supply agencies can pay less than the going rate, and there may be no pension or sick pay. Now, it seems, you are disadvantaged even when you land a full-time job.
Primary teacher Clare Pickup was shocked to learn, when she joined the staff at Balladen primary school in Rossendale, Lancashire, that her previous year's labours as a supply had not counted towards her progression up the pay scale. That was almost pound;2,000 off her annual salary. It also meant she was still another year away from crossing the threshold - another pound;2,000.
Her crime was to have spent part of the year teaching through a private supply agency. Using a little known loophole in the nationally agreed school teachers' pay and conditions, Lancashire was able to dismiss this work as not relevant service - even though Clare had spent the year working in its schools.
To add insult to injury, Clare says she only turned to the private sector because Lancashire's own in-house supply agency - Lancashire Training Agency, run with Reed Employment, a private firm - had been unable to find her enough work.
Clare had moved to Lancashire from Croydon, south London. Jobs are in short supply in the North West, but supply helped tide her over and get to know the area. She signed up with Lancashire Training Agency, but says: "They never rang me. When I did work for them, they never paid me properly; they made mistakes. So I stopped working for them. In the end, I've lost out."
Teachers must work 26 weeks out of 52 for it to qualify as a year's service. Even covering a single lesson in each of those weeks is enough to count. But the pay document stipulates "a teacher employed by a local education authority or a governing body".The distinction is deliberate and has in fact been toughened up in this year's agreement.
In a terse letter to the NASUWT, Clare's union, a Lancashire local education authority personnel officer writes: "Any teaching service where an agency is deemed to be the employer is not recognised for incremental credit under the 26-week rule."
A furious Clare said: "It's all about money. Lancashire Training Agency is losing work because the other agencies are giving a better service and charging schools less, and the LEA is taking it out on the teachers." Her headteacher, Graham Porter, said: "I just couldn't believe it when Clare first told me. I and the governors thought it iniquitous."
And Jane Scott, managing director of Key Stage Teacher Supply in Blackburn, said: "If it had just been the odd day here and there, fair enough. The fact is, Clare went into a long-term position and undertook responsibilities as though she were a permanent member of staff. They're not recognising the blooming hard work she did - all the planning and preparation and parents' evenings."
The Employers' Organisation, which represents education authorities in consultations on the national pay and conditions document, says the pay scale is not a reflection of work done in schools but of work done under the terms of the document. That may seem a fine distinction to teachers working in state schools and paid by the state but via a third party. But the organisation argues that teachers working under the contract are entitled to certain benefits - but also have certain obligations, for example, in terms of further training. Agency work does not have the same status.
"This is a statutory agreement. There are ways of paying correctly," says Andy Inett, the Employers' Organisation's assistant director. "There are certain areas of this arrangement we could simplify and make work better, but it would come down to a judgment as to what sort of experience outside of the maintained sector was of the right sort."
But is this just the old rivalry between public and private sectors? Teachers' unions have been slow to challenge the agreement. They disapprove of the poorer pay and fewer perks supply teachers get and would like to see them all paid according to the contract.
Local authorities too may see supply agencies as rivals, or as threats to their authority in an era when the private sector is eating away at state education. They may also resent the higher costs to schools of using supply agencies.
Lancashire's neighbouring authorities take the same line as the Red Rose county. But others, in the South East - where the private sector is stronger, teachers are scarcer and local authorities have been forced to reach more of an accommodation - appear more flexible.
Technically, teachers' pay is in the hands of governors. But Balladen is typical of many schools that have opted into their authority's pay policy.
It saves time and effort - the authority negotiates the policy with unions on heads' behalf - and puts all schools on an equal footing. But part of the agreement means all grading is deferred to the council.
It took nine months for Clare's case to be resolved - and then only because the school, which had initially employed her for a year, gave her a permanent post. Mr Porter resubmitted her contract with the extra point. It went through unchallenged and will even be backdated.
Mr Porter says the council was "morally wrong even if it was legally and technically correct" to oppose the point in the first place. Balladen's governors are now considering abandoning Lancashire's pay policy completely.
"But it's ridiculous that we should be looking for ways to circumvent a pay system when the whole system has to be brought up to date and modernised to take account of the private sector," says Graham Porter. "There must be other people in Clare's position. She's possibly just the tip of the iceberg. The DfES (Department for Education and Skills) should be looking at this as part of the conditions of service. If there is a desire for all these independent companies to work in education, it needs modernising."
Lancashire County Council declined to comment on the policy or on the failure of their supply agency to find Ms Pickup enough work. But Mr Inett has one useful, if belated suggestion.
"Our advice (for teachers on a long-term supply placement) would be that they should be given a proper monthly contract rather than a supply rate."