Reasons for exclusion were collected for the first time in 2003-04. There is no category specifically on ‘carrying a knife'. There are categories for verbal abuse/threatening behaviour and for physical assault.
The latest data available are for 2006-07; information on exclusions for 2007-08 is scheduled to be published in the summer.
Information on reasons for exclusions is published as follows:
2006-07
Tables 9 and 10
http://www.dcsf.gov.uk/rsgateway/DB/SFR/s000793/index.shtml
2005-06
Table 8
http://www.dcsf.gov.uk/rsgatewav/DB/SFR/s000733/index.shtml
2004-05
Table 11
http://www.dcsf.gov.uk/rsgateway/DB/SFR/s000662/index.shtml
2003-04
Table 11
http://www.dcsf.gov.uk/rsgateway/DB/SFR/s000582/index.shtml