John Spencer has insisted the British and Irish Lions would have won their Test series in New Zealand with just one more week's preparation.

The Lions' 2017 tour manager is determined to see the famed touring outfit receive extra preparation time for future tours.

Warren Gatland's squad pulled off a drawn series against the back-to-back world champion All Blacks against all odds, having flown out to New Zealand just two days after the Premiership and PRO12 play-off finals.

The Lions opened their tour with a patchy 13-7 win over the Provincial Barbarians just three days after arriving in New Zealand, but shrugged of all those problems to win the second All Blacks Test 24-21, and draw the third 15-15.

Spencer insists the Lions are making good progress on convincing rugby's global administrators to add an extra week's preparation to future Lions tours, but also conceded another week this summer could have made all the difference against New Zealand.

Asked if the Lions would have won the All Blacks series with an extra week's preparation, Spencer replied: "My honest opinion is yes; the preparation is extremely important.

"But I think we're making very positive steps already, to talk about and rectify that situation.

"I've received incredible cooperation from the board on that, and there are four of us who are ex-Lions there who know about the intensity and preparation.

"What I would say is that gold medals are won on the training pitch a long time before they are won on the match pitch."