Northampton Saints flanker Calum Clark believes he is running out of time to make a claim for international honours.
The 25-year-old has represented the Saxons and been a member of England training squads, but is yet to be given a Test cap by coach Stuart Lancaster.
"I've got huge ambition to play for England. And it's kind of at the stage of my career where it's now or never," Clark told BBC Radio Northampton.
"It's about trying to make it happen I guess," he added.
England are without a number of forwards for next month's autumn internationals, predominantly in the prop department with Alex Corbisiero (also of Northampton), Mako Vunipola (Saracens) and Dan Cole (Leicester) ruled out.
|England's 2014 autumn internationals|
|Saturday, 8 November v New Zealand|
|Saturday, 15 November v South Africa|
|Saturday, 22 November v Samoa|
|Saturday, 29 November v Australia|
But Lancaster may also need cover at flanker with Exeter's Tom Johnson facing neck surgery and Clark's club-mate Tom Wood a doubt with a back problem.
Clark, who will start at blind-side flanker away to London Irish in the Premiership on Saturday, said: "I need to be going out there every weekend and doing the things you're meant to do, working in training on the things you need to improve on and England think you need to improve on."
However, he believes his style of play may not make him stand out against potential international rivals.
"I always like to be first to things when the breaks are on and that usually means I'm in the breakdown rather than out there hitting lines or making the big plays," added Clark, who has played 109 times for Saints since joining from Leeds in 2010.
"Some people will value it, some people won't. I know what I'm doing, I'd like to think I'd add value to the team. If people see that then great, and if they don't, it's a shame."