One in five brides ask their bridesmaids to sign a pre-nup - and would sack anyone who refused

But get pregnant, put on weight or even change your hairdo and you could be sacked.

In any other job such transgressions would not be grounds for dismissal, but a survey shows that brides-to-be are becoming much more businesslike about picking their wedding day companions.

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More than one in five women planning their wedding would ask their bridesmaid to sign a written pre-nuptial agreement.

Almost half (48 per cent) said they would sack those who did not abide by the contract.

The survey, commissioned by You & Your Wedding magazine, asked more than 1,000 women which clauses they would like to see in a contract.

Favourite answers included not putting on weight, not getting pregnant intentionally and not changing a hairstyle before the wedding day.

More than six in ten (61 per cent) picked a best friend as their choice of bridesmaid, while just under half (49 per cent) chose their sister. Those surveyed also revealed some examples of how bridal relations had turned sour.

One woman said her maid-of-honour left her dress at a service station on the way to the wedding after deciding she didn't like it.

Another revealed a bridesmaid had left 30 invitations un-sent in her desk drawer. But the brides were not always the innocent party.

A total of 15 per cent admitted they were planning to take steps to ensure they were not upstaged by their bridesmaids, while 14 per cent said they chose their attendants because of family politics.

The magazine has devised its own contract outlining how a bridesmaid should act, including not consuming more than 10 units of alcohol or making any inappropriate advances towards male guests.

Colette Harris, editor of You & Your Wedding, said: "Planning weddings can be a stressful time for brides, and management issues with bridesmaids can ruin both the anticipation and the big day.

"While our contract is meant to be tongue-in-cheek, the survey demonstrates that issues with bridesmaids are of concern. Perhaps contracts are the way forward."

Brides may be taking a more businesslike approach because so many are now paying, at least in part, for their own weddings.

A survey by the Alliance and Leicester found 80 per cent of couples pay, largely because they are marrying later, when they are more likely to be financially independent.

With the average wedding costing more than £25,000 it is no wonder they want every little detail perfect.