Hi all, thanks for advice and feedback. All instances have been where both dogs, mine and other been off lead. And always when his female Rottie friend present. Not sure if this factor however as other males approach and he does not go into manic protective/territorial mode. Thing is she does her nut and attacks Bouncer when he kicks off with other dog. Very frighteneing to watch tonight, was well and truly locked onto westie by throat, then started shaking as per usual. Poor westie was only just gurgling, bloke (police officer was crying), blood all over both dogs. Mate, (rotties owner) helped get my dog off. Very strange in that 5 mins earlier, golden retriever came along growling and barking and my dog totally ignored it, wasn't remotely interested.Then wallop, piled into westie who had done nothing, didnt even have toy nearby to get all funny about. Very unpredictable and unstable, have tried allsorts to reinforce my position as pack leader, but still ultra aggressive in some cases. He was attacked at 9 months by huge male rottie and even though young, went ballsitic and had to prise him off dogs head which resulet in owner making complaint against me and dog. Was subsequently discovered that rottie had attacked 3 or 4 dogs in days beofre Bouncer, and someomne suggested that this may be cause of aggression, but surely he wouldn't play with best mate rottie if that was case. Choc lab at park doesn't get on with dogs on leads and has had him 3 times when he's been on lead and maybe cause of pre-emptive strikes, as different choc lab turned up last week and he ran 200 yds and piled into it thinking it was his old adversary.Another friend at park has jack russel and yorkie, two most yappy and aggressive dogs iv'e come across and they always snap and snarl at Bouncer and hes has never batted an eyelid. Very unsure of where to go next other than vet, would't dare take him to training classes in case of kick off again. To be honest his actions tonight were indefensible and wouldn't be at all surprised if copper makes complaint and goes the whole hog. Have told wife to expect knock on door from police, probably wont even involve dog warden again.As for people has never once displayed any aggressive tendencies whatsoever towards humans, not food aggressive, not toy or territory aggressive, just loves people and loves a fuss. As per Celestes post, on a couple of occasions hes has done as her dog and gone almost ridig and then bang, no growl or warning, just wallop.Am at a total loss what to do, feedback and advice most welcome. Am currently waiting for 5 figure cheque to arrive ref out of court settlement from former employer for sacking me for nothing, will be making donation to funds and would like details of payment methods please as being unemployable, bank wont let me have card or cheque book. Thanks again Dobbo.