Bid4Spots is launching a reverse auction marketplace for radio airtime in the United Kingdom in the third quarter of 2007.

Bid4Spots UK is being advised by British radio advertising specialist RadioWorks, and U.K. advertising veteran Paul Mitchard has been appointed to manage operations. The value of the UK radio market is estimated to be £800 million.

Bid4Spots bills itself as offering a more effective way to connect advertisers with broadcasters. Under the reverse auction model, radio stations compete for advertisers and bid the ad rates down. Advertisers and agencies gain simple access to radio at competitive rates. Broadcasters get a flexible way to sell last-minute airtime, increase revenue and attract new advertisers.