Well, if you're in London you're better off than most other parts of the country, as there is a huge range of IT work around in London. Getting a job with little or no experience and no degree will be tough, but you (your friend) can explore various options e.g. networking, acquiring relatively low-end skills that you can exploit to get your foot in the door, and so on.
Networking:
Google for "Java user groups london" and you'll probably find lots of options, hopefully including some near you. Also look at meetup groups e.g.
http://www.meetup.com/Londonjavacommunity/ and the many venues that offer informal talks and techie get-togethers e.g. Skills Matter
http://skillsmatter.com/user-group/java-jee/london-java-community
If you're looking at other languages/tools etc, do similar searches for those terms. And check your local college as you might find study opportunities there, possible careers advice on getting into IT, or at least some options for networking with other people interested in IT.
Go along to meetings, talk to people and - if the opportunity arises - offer to help out with any projects other people might be running in their own time. This will give you a chance to learn from more experienced people, and perhaps lead to other opportunities down the line.
Skills:
Take a look at what you can offer right now, compared to what the job market seems to be demanding in your area e.g. look at tech job sites like
Job Server. Although you probably won't see any entry-level jobs there, it will give you an idea of what skills are in demand locally.
One area you can learn on your own from books/tutorials to some extent is basic website development e.g. using a mix of PHP, JavaScript, HTML, CSS and one or more of the widely used content management systems (CMS) such as WordPress or Drupal. Don't rush into taking responsibility to build somebody's website on your own just yet, as there is more to a robust and maintainable website than just a few pretty pages, but maybe look for opportunities to work with somebody who knows what they're doing (especially with regard to security). One option might be to focus initially on customising templates for CMS like WordPress, as this is mainly front end work without too much heavy duty programming, but it's the kind of thing the customer really likes to see and might be willing to pay for. Even if this kind of work isn't your long term goal, there's a lot of it around, it can often be fitted around your day job, and it may help you to get some IT experience on your CV.
All the noise about London's "Silicon Roundabout" is largely hype, but there are quite a few web-based businesses setting up there, so it might be worth trying them out for some internship work if you can offer them some basic IT skills and can afford to work for free/peanuts for a few months. Also maybe look at working up some simple demo projects - or websites - to illustrate the skills you've managed to acquire so far, as this may be a quick way to distinguish yourself from the people who simply say they can program but have no evidence for their abilities.
Incidentally, the public sector is always short of IT skills, even at a relatively low level, and these days there is a lot of pressure to reduce dependence on agency staff etc, so many organisations are recruiting entry-level staff instead. Talk to your local careers office to see if they can point you towards any suitable opportunities.
Volunteering; Look at
http://www.it4communities.org.uk/
Learning more:
Your local college may teach IT evening classes/weekend classes, often towards industry certifications, although you're already acquiring these of course.The Open University offers computing courses, many of which are excellent, although these are very expensive these days and they've cut the range of courses available following changes to government funding.Coursera is a great place to find free online courses on a huge range of techie topics, including basic programming/web development. You might well find that some courses have local groups in London where you could learn more and esxchange ideas.Also check out Udacity which offers fewer courses but may be more flexible as you can work at your own pace.
Good luck.