Professor Bott from Birmingham University asked the students to evaluate different structures and trends in private number plates. They came back with various theories, the main attraction were the registration plates with the number one in it. The next were the most popular letters, number plates with the letters J R M were amongst the most popular . Although cherished number plates that were short were also popular, such as A1 probably being the most sought after. There are many reasons the values have risen over the years, supply and demand is probably the main reason, in any market place if the demand is greater than the supply the prices always rise. This is probably the reason the DVLA only have so many auctions per year so as not to over supply the registration marks into the market place. Looking at the last twenty years they have made significant gains, most personalised number plates have risen more than investing in stock market , some have risen as much as 400%.