Shimla, Aug 19 - Bharatiya Janata Party (BJP) veteran Jaswant Singh's expulsion from the party has to do with more than just his controversial book on the subcontinent's partition, a senior BJP national leader said Wednesday night.

'The writing of the book was not the only, but one of the several reasons, for his expulsion by the party,' the party leader told IANS here on condition of anonymity.

The BJP earlier in the day expelled Singh from the primary membership of the party. The move came two days after the release of his book, 'Jinnah: India, Partition, Independence'.

BJP president Rajnath Singh told reporters here that the party's parliamentary board decided to expel the former external affairs minister from the primary membership of the party.

He too indicated that Jaswant Singh's criticism of the party after the parliamentary poll debacle was also among the issues that led to his expulsion.

In June, Jaswant Singh stated at the party's core group meeting at the residence of party veteran L.