Secateurs at dawn!

The Chelsea Flower Show opens tomorrow - but not everything in the garden is lovely.

A feud between two leading designers threatens to take the bloom off the event.

TV presenter Diarmuid Gavin and fellow competitor Bunny Guinness are creating gardens next to one another.

But a minor disagreement over the height of a wall has blossomed into a spectacular slanging match.

Now the pair, who are both vying for the Royal Horticultural Society's prestigious Chelsea gold award, are no longer on speaking terms.

Dublin-born Mr Gavin, whose garden features multi-coloured balls on sticks, has accused 46-year-old Mrs Guinness of being 'two-faced, snobbish, elitist and rude'.

In return Mrs Guinness, a six-times gold medal winner, claims Mr Gavin has been 'verbally abusive' and has hyped up their disagreement to improve 'low ratings' on his BBC show Diarmuid's Big Adventure, which is following his progress at Chelsea.

Tempers first flared when the two disagreed on the exact height of two walls between their gardens.

Both were meant to be 6ft tall but Mr Gavin's was a little higher. The problem seemed to be nipped in the bud, however, when he proffered a bottle of champagne.

But hostilities began again after an interview on Radio 4's Gardeners' Question Time.

Mrs Guinness, a panellist on the programme, was asked to set up an interview last Wednesday with Mr Gavin on the site of his garden, called A Colourful Suburban Eden and funded by the National Lottery.

Mr Gavin, 39, apparently became angry when interviewer Gill Pyrah asked how much he had spent on the garden, rumoured to have cost £300,000. He said yesterday: 'I didn't care about being asked how much the garden cost, but it was the way she asked questions.

'Her first question was, "Do you think you can buy a gold medal?" She made rude comments about my garden. It was the rudeness that upset me.

'They said the geraniums I am using were common and then asked how anyone in suburbia could afford a Dicksonia, which is a Tasmanian tree fern.

'After the interview, they walked off laughing. It was all a complete set-up.

'I shouted at Bunny afterwards because I was absolutely furious. They were so rude. It's made it a very unpleasant place to be in the past few days.'

Mrs Guinness said: 'The next day he came up - I thought he was going to apologise - and he hurling abuse and saying-I had set him up. 'He said I was a nasty piece of work. You could hear him right across the avenue. It was very embarrassing.'

Members of Mr Gavin's BBC TV crew said he had been 'ambushed'. They claimed Mrs Guinness was jealous because she had less money to spend on her garden from her sponsors.

But she insisted there had been no set up and said Radio 4 had sent a letter to Mr Gavin explaining she had nothing to do with the line of questioning.

She added: 'I've tried to talk to Diarmuid about it but he just yells abuse at me.

'He could have a controversy with a goldfish. He's probably dramatising this because ratings for his show are low.'

The flower show's director Stephen Bennett said the organisers would not get involved, but added: 'Diarmuid could well be doing all this for dramatic effect. He's a sort of loveable nightmare.'