My Border Terrier is usually lovely with other dogs - but quite submissive to start with (she rolls onto her back with paws in the air).  But she has always now and then barked at dogs when she and they are on leads (usually when she doesn't have the chance to say hello to them).  She is doing this more and more and its hard to tell if its through excitement (at seeing another dog) or frustration (at not being able to get to it) or agression.  I also don't have a clue as to how to deal with this or stop her - can any one offer any advise.

Many thanks

does anyone have any thoughts??

Please help!!
THanks

Probably frustration, as she is not being allowed to play.

Find her ample opportunities where she can regularly mix with safe dogs off lead and then dogs on leads will become less attractive and therefore reduce the frustration.

my springer spaniel does accactly the same thing and as done since she was born, i think it is a combination of frustration at not being able to get to the dog and not being able to say hello.
i have tried letting my dog say hello, but that does not work as she gets so excited she still whines and wimpers.
sorry i also wish to know how to stop this.

Hi my Border Terrier Robbie does exactly the same when out walking he knows where certain dogs live and creates such a fuss when passing there house also when passing certain dogs (not all dogs) on there lead like yours he goes on alarming and on one occasion when a dog who was not on the lead came up to him he really set too in a  proper dog fight yet all the time his tail is wagging.
Robbie is now three years old and this behaviour only started over the last six to nine months, in an effort to correct it I enrolled in a dog training class last January and slowly I can see signs of improvement I avoid taking him passed the houses which I know will encourage his bad behaviour and always have treats with me and plenty of praise when he walks passed a dog on the lead without reacting I am no expert so don't feel I should be giving you advice on what to do but speaking as someone who as gone down the same road with my Border I do advice you enrol in one of your local obedience classes good luck