THE work of select committees is seldom covered in reports about parliament but they are probably the most powerful bodies in the place.

Their chairs are elected by the whole house for a parliament giving them a degree of independence which is very valuable and members are elected by their respective parties, with some places being very hotly contested.

Anyone who saw the joint session of the work and pensions and business select committees last week as they grilled the executives of Carillion will know that you should not treat appearing before a committee lightly.

Indeed, one former ambassador was given such a mauling that I was told afterwards that the Foreign Office used the video to instruct staff on how not to behave in front of a committee.

These gruelling sessions are usually reserved for powerful people and the petitions committee, which I chair, adopts a different strategy when dealing with members of the public.

When we are talking to families effected by brain tumour or to parents who have lost children, we try to adopt a more informal approach. Sometimes we have a roundtable discussion instead of the usual style of committee hearing and at other times, we need to reassure our witnesses that, even in a formal setting, they are not going to be grilled.

That was why, last week, I found myself meeting Katie Price and her mother, Amy, to explain the procedure to them.

Katie had started a petition about online abuse following disgraceful comments directed at her son, Harvey, who has serious disabilities.

We heard from her family about their experiences and followed it up with evidence from other people representing organisations for disabled people.

All of them gave powerful evidence about the abuse they had suffered and the need to take action against those who perpetrate it.

Social media can be a powerful force but it can also allow some very unpleasant people to target others in a way which is totally unacceptable in a civilised society.

Members of the committee were profoundly disturbed by what they heard and decided that, rather than just debate the petition, we would first produce a report, with recommendations for government action.

This is an important way for people to have their voices heard in parliament and to influence the issues MPs debate. The committee is fairly new but I think that everyone has seen how valuable it is. And we can still grill people when we need to!