Anna Verrall's final pay cheque came through last week. For the next month, unable to afford the deposit to rent a flat, she will be sleeping on a friend's couch.
The 27-year-old, who has six years' teaching experience in New Zealand and the UK, has spent the past year working with some of west London's most troubled young teenagers.
But as a supply teacher, her expertise counts for nothing when summer arrives and the money dries up.
For thousands of such teachers, the summer brings a six-week financial drought and the prospect of pulling pints, waiting tables or living off credit cards.
Last summer, Miss Verrall had no work "so I basically ate up my entire savings", she said.
This year, her agency has found her work running a school holiday programme, paying pound;315 a week, before tax - half what she earned as a specialist teacher.
"I won't be going out, I'll be buying budget groceries, and definitely not having new clothes or summer trips away," she said.
Miss Verrall has spent the past year working at an Ealing pupil referral unit for 12 to 14-year-olds with learning or behavioural difficulties, most of whom had been kicked out of their schools.
Her work involved more than its fair share of planning, administration, meetings with educational psychologists, and working one-to-one with students.
But supply teachers, despite their increasing importance to the school system, have no employment protection in the holidays.
One teacher said she had "sponged off" her aunt in Leeds one summer, and was supported by her boyfriend the following year.
But she regarded it as one of the sacrifices of teaching: "You're not there to make a mint. You're a teacher, not a plastic surgeon. Get tougher."
Another said her school paid the agency pound;200 for each day she worked, of which she received pound;125, before tax. Even with holiday pay, she would still have to get work every day of the academic year to match a junior teacher's salary.
She said supply teachers had to save, then tighten their belts and grit their teeth over the summer. One friend was privately tutoring over the break, while another was relying on her boyfriend to support her.
Hannah Renshaw, a recruitment consultant at Premier Education in the North-west, said she was placing jobless teachers in nursery work for the summer, even though it paid only about pound;50 a day.
Sonal Ladwa, at TeachLondon, said: "We advise them to apply for work with office temping agencies such as Office Angels, or to ask their local pub whether they have any spare shifts available."
The National Union of Teachers wants a return to pools of supply staff, maintained by local authorities, to provide career structure and security, and save schools having to pay agencies.
A spokeswoman said that in the past many supply teachers were "backpacking Aussies who come to Europe for travel", so they were happy to save money to go travelling. Others did not want to be working full-time, perhaps for family reasons.
"Unfortunately, a lot of newly- qualified teachers are now being forced into supply teaching as well. It is the most difficult role, walking into a classroom without knowing the pupils," she said.
She advised teachers to show flexibility and be willing to work further afield to get a contract with a school, rather than becoming trapped in supply teaching.
'IT'S UP TO THEM TO BUDGET'
* Official figures show there were 14,700 supply teachers at the last count. This up from the 13,610 when Labour came to power in 1997, but down from the peak of 19,580 during the height of the teacher shortages.
* Statistics for January show that a third of supply teachers were hired through agencies.
* Pay rates range from pound;95 to pound;135 a day.l John Dunn, of Select Education, said his agency included holiday pay as a percentage of the daily rate. He said: "Full time supply teachers will be earning more than Pounds 26,000 a year. It is up to them to budget to spread that throughout the year."