Barring a last-minute backtrack, on Thursday morning the Tour de France organisers ASO will purchase 49 percent of the Tour of Spain.

According to the Spanish sporting press, the deal is expected to be signed in Madrid at midday in a lawyer?s office. Rumour has it that television company Antena 3 will retain the overall control, with current Vuelta director Ignacio Ayuso remaining the race?s top executive.

However, the influence of ASO will be felt almost immediately. The whole of the Vuelta?s logistical apparatus, plus the commercial and marketing aspects of the race, will apparently be run by the French media and sports giant.

ASO will also – most importantly – handle the sporting side of the Vuelta. This could mean that there could well be changes in the structure of the race in the future – or perhaps in the dates. Officials in the Vuelta have recently expressed an interest in returning to their April slot and reducing the number of race days to two weeks and three weekends.

The expected purchase will not affect Alberto Contador and Astana?s participation in the Vuelta this September. Astana have been barred from the Tour this year. But it is understood that ASO consider that the Kazakh squad have already ?paid their dues? in the Vuelta for earlier doping scandals by being banned from the race in 2007.

The news will not be welcomed at the UCI headquarters at Aigle, where there have been frequent accusations that ASO are plotting to start a new alternative cycling league. Gaining such a big influence over the Vuelta could be seen as additional proof for such conspiracy theories.

Half-shares in the Vuelta certainly represents an important addition to the large number of bike races – 10 – and newspapers owned by ASO. ASO also run Paris-Dakar, the Paris marathon and golf?s French Open.