Part-time is such sweet sorrow for stores: Burton's mass sackings this week are a belated highlight in an established trend in the retail sector. Patrick Hosking reports

Burton Group's decision this week to sack 1,000 full-time shop assistants and replace them with up to 3,000 part-timers reflects a trend that has been going on for more than a decade.

About one-third of all retail staff are now part-timers, and the proportion is expected to grow as employers seek to bear down on their wage bills and match staffing levels to the peaks and troughs of high-street traffic.

According to Richard Hyman, managing director of the consultants Verdict Research: 'In retailing only two costs really matter: occupancy costs and wages.' Stores cannot do much about rents and rates, which are still rising, although more slowly. So, with sales sluggish, the pressure is on to crack down on wages and related employment costs. Switching to part-timers is very attractive for budget-conscious managers.

Part-timers are usually paid a lower hourly rate than full-timers. The employer pays no National Insurance on employees earning less than pounds 54 a week gross. And there are fewer pension and legal obligations: for example, employers do not have to pay statutory redundancy pay to staff working fewer than 16 hours a week.

Moreover, part-timers give the flexibility to field more staff in peak trading times - lunch hours and Saturday afternoons - without having them standing idle in quieter periods.

Burton's need to attack its labour costs was acute. Its pounds 289m annual wages bill represented 18 per cent of sales last year, a higher proportion than any of its near competitors. Sears was 15.5 per cent, Storehouse 14 per cent.

According to John Hoerner, chief executive of Burton, the change should result in improved service in the stores, which trade under the Top Shop, Top Man, Dorothy Perkins, Principles and other facias.

The total redundancy payout for these job losses, plus 933 cuts in the head office, is pounds 10- pounds 15m. This will be paid back in cost savings in this financial year.

The supermarket groups led the move to part-timers a decade ago, when the introduction of scanning equipment in the check-outs accurately showed the erratic pattern of trading.

There are some disadvantages for employers. By definition, part-timers are less experienced. Lack of product knowledge upsets customers. Training costs go up. Rostering becomes more of a headache.

While the shift is mainly positive for employers, it is mostly negative for employees. They are generally paid less, enjoy fewer benefits, and have little or no job security.