Hi Louise, laurel is a possibility, but not the fastest growing to that height. It also is best trimmed by shears/loppers, not a mechanical cutter, to save brown edges to the cut leaves, so to maintain in the future you may not want that.
There are Escallonias that grow pretty quickly, IME, are evergreen & also have flowers. Taller varieties of Mahonias are quick growers, prickly if needed for security & also flower in the winter. Pyracanthas too, flowers, berries & thorns- again can be pruned to 'hedge style'. Holly is slow but can become a good hedge in time.
You can use conifers, as long as you are prepared to keep them trimmed to the height allowed/wanted. Dont forget the width too, they dont just 'go up'. Any hedge will dry out the adjacent soil with its' roots.
Having a path next to the hedge will allow easier access for maintenance to it, so although it initially feels as if you are losing some garden, true, it does make life easier in the long run. Trying to trim a hedge whilst not damaging emerging/growing bulbs/plants isnt easy!
A mixed hedge eg different plants, evergreen & deciduous could also be a possibility- hawthorn for instance is wonderful for wildlife & again has thorns if needed. BTW thorns wont be ideal with young children in the garden.
Are you sure that you will be allowed a high hedge? Your council may insist on 2m/6' 6''. Also if the boundary adjacent to a public area eg footpath/road then thorns, although a security help, are a 'no no' in this day & age of compensation etc. J.