DURING the past four months, Mr Andy Neilson has single-handedly expanded the size of the Royal Hongkong Police by adding hundreds of beat constables, dog-handlers and PTU officers - and this ''new force'' is still growing. Unfortunately, the problem with these new recruits is that they are only 54 mm high. Yes, you guessed it . . . they are toy policemen. Mr Neilson owns a unique shop in Pacific Place that specialises in all kinds of vintage collectables, and he has sold toy soldiers to some of Hongkong's most prominent figures - Secretary of Finance Mr Hamish Macleod, Hutchison Whampoa group managing director Mr Simon Murray, and former governor Lord Wilson, not to mention overseas collectors like pop star Phil Collins. Mr Neilson is a former Royal Marine Commando who came to Hongkong to train as an inspector with the local police force. He also worked with the Police public relations department for a period, so had no problem capturing the ''police image'' for his new figurines. The Royal Hongkong Police gave its blessing to the range of figurines, which are dressed in summer police uniforms, and even illustrated Mr Neilson's figurines in a recent issue of the force magazine Off Beat. ''Using some of my friends still in the force as models, I took lots of photographs and made numerous sketches to get the exact pose and uniform details,'' Mr Neilson said. He said these illustrations were then sent to his factory in Shenzhen to be carved as master figures before being cast and painted by a team of over 30 skilled painters. ''Among the upcoming figures are a motorcycle policeman, a policewoman and a riot squad,'' he said. At present, prices range from $95 and up, but Mr Neilson expects prices to rise in the future as his figurines are becoming ''collectors' items''. According to the experts, many men are prepared to spend a small fortune on their favourite toys. ''The majority of our customers are grown men who have never really grown up in terms of their interests and hobbies,'' Mr Neilson said. ''Playing soldiers or policemen is a bit like a throwback to your childhood, and so it's a passion fathers share with their children.'' Another reason for their popularity is that they are some of the few toys children really look after. ''They take real pride in their collection and they become interested in history.'' A collectors' item? Well, if not, that seems to be working as an appropriate justification for an expensive grown-up toy.