Little Sam McCausland's parents Tracy and William, who set up the charity 'pleasefixsam', were joined by 23 other jumpers as they leapt out of an aircraft at an altitude of 13,500 feet - or 2.5 miles above the ground - raising between £8,000 and £9,000 in the process.

Tracy described it as 'an amazing experience'. She explained each member of the group had taken part in 'tandem jumps' with experienced parachutists.

"We had 45 seconds of freefall followed by four minutes of blissful silence as we gently swung under the canopy with the most amazing views of Northern Ireland," she added.

"There were a few rough landings but everyone survived unscathed and most were talking about doing it again."

Also taking part in the sponsored jump were Clive Anderson, Acting Principal of Knockmore Primary School and Ellie Stirling, one of his P1 classroom assistants.

The McCausland's elder son Callum attends the school's specialist Speech and Language Unit and Tracy described the staff's efforts as 'fantastic'.

"Parents from the school have been very generous in their donations," she said.

She also expressed gratitude to Lisburn woman Gayle Currie who arranged the parachute jump in conjunction with the organisation 'Moonjumpers'.

Tracy said 'pleasefixsam' was a completely voluntary charity: "We have no salaries, no overheads and no costs - everyone involved gives their time, skills and products for free so that we can guarantee that every single penny raised will go straight into the hands of the researchers," she said.

"If anyone can help in any way please get in touch. Our website - www.pleasefixsam.com - now features ideas on how people can help.

"We are still encouraging people to get involved - if anyone would like to jump we will be continuing to work with Moonjumpers throughout the summer and into the autumn - register by emailing info@pleasefixsam.com or call 92680078."

Tracy also thanked Coca Cola and Subway who provided the parachutists with much needed refreshment.