1. Incapacity Benefit (which is dependent on having a qualifying National Insurance contribution record) is not means tested, & having the compensation money would not invalidate a claim. However, it would invalidate a claim for any means tested benefits, such as Housing Benefit or Council Tax Benefit. It is for that reason that personal injury compensation is often put in a trust.
2. People on Incapacity Benefit are gradually being changed over to Employment & Support Allowance. This has 2 elements - one is not means tested & is based on National Insurance contrbution records; the other is means tested. Anyone changed over from Incapacity Benefit already satisfies the NI contribution record so their ESA is not means tested. However, the Government is proposing to limit the non-means tesated element to a maximum of 12 months.
3. Job Seekers Allowance also has both means tested & non-means tested (NI contribution based) elements, but the latter only lasts for 6 months.
4. So far as I can see from the original post, there is nothing to stop the poster making use of the money in the trust other than obtaining the agreement of the trustees.