Mbesuma has joined from South African champions Kaizer Chiefs where he scored 35 goals last season.

"Everybody knows his goalscoring rate is phenomenal and he deserves his chance in the best league in the world," said Portsmouth chairman Milan Mandaric.

"He has to be allowed time to settle into his new surroundings but we have now signed seven players and all of them

internationals."

Chief executive Peter Storrie believes Mbesuma can become the long-term successor to Nigerian ace Aiyegbeni Yakubu who was sold to Middlesbrough for £7.5million at the end of last season after scoring 19 goals in each of his two Premiership campaigns at Fratton Park.

He, too, needed to appeal against the rejection a work-permit renewal.

Storrie, who attended the Mbesuma appeal hearing, said: "As in all transfers there is an element of risk and Collins will need a period of adjustment here but he has exceptional talent. The right decision has been made.

"Yakubu was a risk when he first came here but in reality it did not turn out that way."

Top clubs all over Europe were said to be chasing Mbesuma.

Despite this, he was turned down for an automatic work-permit to play in this country two weeks ago after agreeing a three-year deal with Portsmouth who are understood to have agreed a price of just £500 000 for him.

The sticking point was that Zambia, although ranked 62nd in Fifa's latest lists, have not figured regularly in the top 70 over the last two years.

Ironically it is Mbesuma's goals - he netted a hat-trick in a recent World Cup qualifier against Congo, scoring eight goals in all in five international games - that have propelled them up the rankings table.

Portsmouth's French manager Alain Perrin has already signed compatriots Laurent Robert - on loan from Newcastle - and Gregory Vignal plus Irish international Andy O'Brien, Colombian midfielder John Viafara, Norwegian striker Azar Karadas and Dutch goalkeeper Sander Westerveld.