My brother in law is here on Tier 1(G) visa expires Sept 2011: he has been working 2nd job as lecturer in private college to boost his income getting average £600 pm for last 6 months but now college says they have always consider him self employed and they do't intend to pay his tax/NI; will this ...

Tier 1 Gen visa will be abolished in April 2011 so you will have to apply under whatever is available then, unless you get a sponsorship from an employer in which case you should be ok