Glen Jackson will still call full-time on playing days if Saracens take title

Jackson, 34, has won the battle with South African Derick Hougaard for the No10 jersey for the crucial final Premiership match against leaders Leicester at Welford Road on Saturday, when victory would give the north London side a home semi-final clash with Northampton.

If Sarries fail to defeat the reigning champions, they will have to travel to Northampton on 16 May to earn the right to appear at Twickenham in a first Premiership final on 29 May — the perfect stage for Jackson to bow out.

The omens for a Welford Road upset are not good, with Sarries having lost on their previous 32 visits, but Jackson takes heart from his team's five away wins this season.

He said: "There is obviously a bit of me that would like to play a bit longer but what could be better than finishing my Sarries career on a massive high by winning the title at Twickenham?

"If we achieved that fantastic honour I may sit in the dressing room and think what am I doing?' but I am committed to starting my refereeing career in New Zealand and have to be back by 1 July for a five-day camp organised for the six full-time referees of which I am one."

Jackson has scored 1150 Premiership points since arriving in 2004 and was voted the Professional Rugby Players' Association Player of the Year in 2007.

He is now creating rugby history in New Zealand by becoming the first player to take up refereeing and he has received an immediate invitation to become one of the country's elite officials.

Patently, it will be a very sharp learning curve for the No10, who has found it difficult to take charge of many university and junior club rugby matches in Hertfordshire this season because of a combination of bad weather and his commitments with Saracens.

It will mean a complete change of mindset and Jackson admits that when watching match videos he finds himself concentrating on what the referee is doing, a clear example of how he is preparing for a new career.

And Jackson has refused to rule out the possibility of officiating at the 2015 World Cup in England, where he could be in charge of matches involving some of his current team-mates.

The former Chiefs No10 said: "The aim in New Zealand is to put me straight into National Provincial level matches, which is going to be a case of sink or swim.

"As I am 34, the decision to stop playing is easier and I am sure it would be a much tougher call if I was younger and, normally, at this time of the season everyone is ready for a break.

"However, thanks to our rotation policy at the club, I feel really fresh and together with the rest of the guys could play for another three months. I have played in a number of semi-finals in different competitions for Sarries but this is the best I have ever physically felt at this point of a campaign.

"It hasn't been a case of the club having to play the best 15 players in every game because we have real depth this season and that's the big difference I have noticed after six years here at Sarries.

"The club are going in the right direction and we have the opportunity to finish the season as champions."