My daughter ,who is a keen swimmer, has made unexpected progress recently, and has just met the European qualifying standard for her age group, but her father, my ex-husband won't consent to her participation in a competition in a few weeks time, just out of spite . What can I do ?

Make an urgent application to the family court to give permission for your minor daughter to participate in the competition overseas.If the court considers the trip to be to your daughter's  benefit,and she wants to participate, it will find in your favour, if there is no objective reason not to do so.