Phil Harrison believes it will be a "difficult challenge" for PS3 to match PS2's sales

Sony's former head of Worldwide Studios, Phil Harrison, believes Sony has a tough road ahead if its to expect PS3 to match PS2's record-breaking sales.

Speaking with Eurogamer in its PS2 retrospective chronicling the system's 10 years on the European market, Harrison believes the "dynamics" today are "slightly different" as the market is much more competitive.

"I hope PS3 can match PS2, but I think the market dynamics are slightly different," he said. "For a large chunk of its life-cycle, the PS2 didn't really have any competition anywhere in the world, so Sony was able to sell a huge number of units. If PS3 does reach the same level it will take longer and it will be a more difficult challenge."

Harrison also belies Sony's ability to secure third-party exclusives for the system was more feasible at the height of its popularity, and it was "the last era" in which you will see console exclusives "happen in a meaningful way".

However, SCE founder Chris Deering has faith in PS3, and is of the belief it will eventually "as many as PS2" and maybe more.

"In the case of both PS1 and PS2, we sold more Slim units than original models," he said. "The PS3 Slim has only been out a couple of years. If you could get a PS3 for a hundred pounds... Can you imagine? It could go much higher and last longer."

As of PS2's anniversary, the console has moved 146 million units worldwide, while its predecessor has moved over 46 million units in four years on the market.