There is no ‘right’ age to introduce solids, as every baby is different.   Current government guidelines recommend waiting until your baby is approximately 6 months old as it is about this time when he/she will start needing more nutrients than are available in milk alone...
However, some babies will be ready before this and will start to display classic signs that they are ready for something a little more substantial than just milk (see ‘Signs that Your Baby is Ready for Solids’).  Starting before 17 weeks have passed from your baby’s due date is not recommended though as the digestive and immune system is not sufficiently developed before this time.

Introducing your baby to solids too early can also increase the risk of allergies and possible obesity in later life.  Similarly, waiting too long to start weaning can result in some babies having difficulty eating foods with lumps a little later on and could also result in nutritional deficiencies.  The best advice is to follow your instincts, let your baby guide you and if in doubt, speak with your health visitor or GP.