An article in The Independent in January
http://www.independent.co.uk/student/career-planning/getting-job/internships-make-a-difference-when-it-comes-to-getting-a-job-1873777.html
made the point that 'graduates flooding out of university in the midst of a recession, they are looking to internships to give them the edge that employers demand.'

Internships are NOT guarantees of permanent employment with a company

- According to the recent Destinations of Leavers from Higher Education survey conducted by the Higher Education Statistics Agency (HESA), "having already worked there" accounted for 17 per cent of job sources.

Some internships are better than others.

Most of the best-quality internships are offered by those who can afford them - big private firms but decently paid internships with a possible position at the end, while obviously the ideal, are scarce, particularly in the recession.

Internships in charities, fundraising, and nonprofit work are more usually unpaid / voluntary.
This can also be true for small firms although under a new government initiative participating graduates will be able to get a grant of £100 a week towards their wages.
This would then be topped up by their small firm employer.

The Internship companies across the UK are profiting from this surge in interest.

IT IS THESE RECRUITMENT COMPANIES AND NOI THE EMPLOYERS WHO HAVE STARTED CHARGING FOR PLACEMENTS.

There are websites charging hundreds of pounds for letters of introduction for internships.!!