HMO ... the housing act 2004 explained

http://www.anthonygold.co.uk/site/ang_articles/ang_articles_housing...

Some useful snippets:

A local authority can, however, decide to extend licensing beyond the scope of mandatory licensing through the ‘additional’ licensing powers (s 56 of the Act). This discretionary power enables a local authority to designate an area where all private landlords of HMO that do not fall within the mandatory provisions must be licensed.

Enforcement
A failure to obtain a licence without a reasonable excuse will be a criminal offence that could result in a fine of up to £20,000 (s 72). A landlord can also be fined for failing to comply with any condition in their licence.

From 6 April 2006, landlords of HMO that are subject to mandatory licensing will have a period of three months to file their applications for a licence. If no application is filed by 5 July 2006, the local authority will in theory, be able to prosecute. The filing of an application will, however, be a defence to any prosecution.

Why doesn't Harringey use these powers?  All HMOs could then be licenced and the council can raise some cash to pay for more planning dept headcount. Basic health and safety checks etc come into force, rogue landlords dealth with etc. Sounds like a solution to me.