You will need a fence at least 5 foot tall to keep out muntjac deer. They breed all year round and can cause real problems in gardens.

Agree - 1.5 metres high (around 5 feet) to keep out deer of any sort. Some more info in the link below (probably more than you need, everything you ever wanted to know about how to keep deer out with fencing) Pages 1 and 5 are probably the most relevant to you - for muntjac, you need some mesh fencing to be buried into the ground at the base

http://www.forestry.gov.uk/pdf/fcpn9.pdf/$FILE/fcpn9.pdf

Thank you all. The joys of living in the country being a born and bred city gal! I always thought they looked so nice! Its impossible to bury in the ground as there are banks and ditches along the boundart (Council owned landadjoining allotments) so thet do nothing not even maintaining the weeds so no hope of them fencing or levelling as they have nativehedging gone wild mostly blackberry.

Well at least you can make jam, pies and crumble with blackberries (or brambles as we would say in Scotland). There is no reason why you can erect your own fence inside the council fence just make sure it is totally separate yet quite close to the existing fence. That may, just, deter the muntjac... If they were roe deer it would have to be a good two metres in height and there is no realistic way to keep red deer out of a garden!