But organisers the Helensburgh and Lomond Chamber of Commerce say the event will still be a huge success, with replacement events called in.

Graeme Houston, the pilot of the Remax Hot Air Balloon, was involved in a serious head on road accident near his home in Biggar, and as a result the balloon will not appear at the Summer Festival.

Although Greame’s two sons escaped unhurt, the balloon pilot sustained injuries meaning he will be grounded for several months.

Roger Ferdinand, Chamber of Commerce board member, said: “We wish Graeme a speedy recovery and hope that we can feature the balloon at a future event.

“All attempts to find a replacement pilot or balloon have proved fruitless and therefore it is with great reluctance that the balloon flights have been cancelled.” Meanwhile, the sand sculpting workshops – sponsored by, and held at, M&T Builders’ Merchants yard in Charlotte Street – are proving popular with bookings coming in fast.

The workshops provide an opportunity for youngsters to have fun whilst learning a new skill. The sculptors will teach the children and their families the tricks of the trade – including how to make sand stand like a snowman and be carved into a castle.

A festival spokeswoman said: “Participants will go away at the end of the day with a knowledge that will help them and the people that they will teach in the future, to make superb sand creations.

“In addition they’ll develop their motor skills and discover or improve their 3D modelling talents.” Those who miss out on a place at the sand sculpting workshops can still get in on the act with Sand Art in Colquhoun Square, brought to Helensburgh by Party Palz.

Budding artists can have a go at making their own sand art pictures to take home with them and Party Palz will also be bringing along some well known characters to meet their fans. Party Palz will be in Colquhoun Square from 10am on Saturday 19.

Youngsters keen to work off some energy can try out the CBF Tennis mini tennis in the Square from 10am to 1pm or netball with Helensburgh Netball Club from 1pm to 4pm.

Also in the square there will be a market with local businesses and a farmers market, a barbecue provided by the Buffet Shop from noon to 4pm, and on the front will be the YOUR Radio sound stage with a line up of entertainment, a fire engine (Saturday only), a Navy RIB, and the Roller Rink which is sponsored by Helensburgh Toyota who stepped in when another sponsor let the organisers down.

The rink will be open to the public on Saturday and Sunday and there will be displays by Glasgow Roller Derby at 10am, noon, and 3pm on Saturday.

Codona’s fairground rides will be open at the Pier Car Park throughout the festival and Waverley fans will be able to see the world’s last seagoing paddle steamer as she comes in to the pier around noon on Saturday.

On Wednesday evening SOS Fitness will be running its ‘Ricky Hatton’ Boxing class in Colquhoun Square, and the evening will be open to anyone over the age of 15. The class will begin, regardless of the weather, at 7pm and run until 8pm.

The following weekend there will be another Farmers Market in the Square on Saturday, July 26 along with a Victorian tea room in a festival tent and another Buffet Shop barbecue.

There will also be a Victorian children’s ‘chair o’ plane’ ride in the square to provide a traditional “doon the watter” excitement.

The Summer Festival Craft Fair run by Visit Helensburgh will be open for business in the Tower (the former St Columba Church).

Yacht enthusiasts will be able to watch the Commonwealth Games Flotilla sail past on its way to Glasgow between 9am and noon on Saturday.

Throughout the whole festival a Commonwealth Flags competition will be running in shops around the town ,as well as a best dressed shop window competition.

A spokesman for the Summer Festival said: “Despite the disappointment over the hot air balloon we are delighted with the way the festival is shaping up and we hope that as many people as possible will come along to join in the fun.

“Keep an eye on our Facebook page, Helensburgh Summer Festival, for any updates.”