MADRID — The World Anti-Doping Agency (Wada) has enthusiastically praised Spain’s doping policies, four years after dealing a major blow to Madrid’s Olympic bid.

"(Spanish authorities) have done things that we think are very significant," Wada director-general David Howman said.

"I think there has been a change in the approach, and I hope that continues."

The comment is of the utmost importance as Madrid approaches the vote on September 7 in which members of the International Olympic Committee (IOC) are to pick the host of the 2020 Games. The Spanish capital is in that race along with Istanbul and Tokyo.

Spain has for years borne the stigma of doping, and Howman is the man who in May 2009, hours before the IOC evaluation commission visited Madrid, destabilised bid officials with harsh criticism of moves to make the country’s antidoping policies more flexible, as proposed by the government of the time.

Years ago, Wada questioned the ban on doping tests between 11pm and 8am.

"We said to them that they should quickly change the law. They said they would do that, modify some aspects," Howman said at the time.

In those days the government, under Jose Luis Rodriguez Zapatero as prime minister, came close to putting in place a decree that moderated Wada instructions. The planned changes incorporated criticism from sportsmen including tennis star Rafael Nadal, who had defined the Wada system as "intolerable persecution".

Howman warned then that this would cause trouble for the Madrid 2016 bid. "We were not informed before we read it in the media," he complained.

"When we read it we said to (then sports secretary Jaime Lissavetzky) it was not wise to have a law like this, also not helpful for the Madrid bid. If you hold Olympic Games you can’t have a law that says you can’t do 24-hour tests," Howman said.

Lissavetzky had to backtrack over the following weeks, but that was not enough to prevent Madrid losing to Rio de Janeiro for the right to host the 2016 Olympics.

Four years later, in a new bid cycle and under a different Spanish government, Howman sees things very differently.

"They’ve changed their laws. And they’ve got a few smaller changes to make. They’re doing that now," he said.

He expects those changes to happen by April. "Then they’re going to be totally in line."

Howman praised the government of Spanish Prime Minister Mariano Rajoy during the London 2012 Olympics. He said he had noticed a change and that things were a lot better under the new government, with a new law against doping and a new local antidoping agency.

Nadal’s latest suggestion, that doping tests are made public, sounds good to Howman.

"He and some of the other top players in tennis have come out and said, ‘We want a stronger programme.’ I think that’s fantastic, because I remember a few years ago when they were very critical of some of the things that we were doing, including the Anti-Doping Administration and Management System (which requires athletes to be available every day for potential tests)."

Even as Howman talked in London, court proceedings around the Operation Puerto doping scandal continued in Madrid. Wada is following those closely but it has an extra demand: it wants all the people whose blood is held in the 200 bags seized to be identified.

"We would not be there if we did not have hope. We would not have spent all the time and money and energy over the last six years to try to get to this situation if we didn’t have hope," Howman said.

"The judge is certainly showing that she wants to hear all the information, which is good, and we’d now like to see the result of the rest of the evidence and the way in which she makes that determination. It would be great for sport if the identity (of the people whose blood is in the bags) was known."