Warning sweeping (and tongue-in-cheek) generalisations follow..
As somebody who has more than enought experience of the IT job marketplace, I'd say the perl segment is on the up - checking jobs.perl.org (even ignoring the 'contract' roles mentioned on the london.pm list) and jobstats.co.uk there is an obvious upward trend, with the number of jobs now about the same as 2001 and close to pre-bubble levels around 1999.
There does seem to be a gap between the run-of-the-mill or junior roles, usually web/new media oriented and competing with the PHP and ASP crowd at 20-25k for the junior and 25-30k for the slightly more experienced perl developer. If you are a single graduate with no hobbies and no mortgage or family to support then there is rich pickings.
At the higher end, there are the Banking/Finance roles which require N years of sybase/db2/oracle, N+1 years Solaris, N+2 years Finance Industry experience and another year or 2 experience of whichever niche software that part of the industry uses, these jobs are a mix of contracts and permie roles and pay 40k to 60k depending on how big the bank is and how many 0's there are in the ammount of money handled by your code every day. Rich pickings if you got into banking a few years ago, otherwise you will have to retrain to Java to get that kind of Salary.
In between there is a scarce and empty wasteland, containing mirages of roles that will never be filled, some of these mirages have been there for months or years but are no more likely to be filled than dark matter is to be found behind somebodys sofa. Of course there are some companies that really do need some developers and actually fill the roles advertised, only having to advertise again because they just can't get enough so they sponser things like ponie ;) Recently there have been a couple of real jobs appear between junior and banking, but they are few and far between.
Anyway, to summarise : there are plenty of perl jobs, but they are mostly at the low end of the market or highly specialised (banking, bio-informatics, etc). Even so I am still finding it better than for a long time. There are also some more interesting roles than I have seen advertised before and with a richer mix of technologies and skills. Perl isn't just used for CGI, it powers stuff from Financial Markets to Genetic Research, serious software testing, ISPs, search engines and pretty much every internet application imaginable.
Sources:
jobserve - perl and london - 222 roles advertised in past 2 days
http://jobserve.com/it/jobserve/searchresults.asp?jobType=*&d=2&page=1&type=&q=perl+and+london&x=0&y=0&order=Rank
jobs.perl.org - 4 roles in 7 days for UK, 2 in london
http://jobs.perl.org/country/United%20Kingdom
jobstats.co.uk - 196 roles for 3rd september, 3% of all roles advertised, ~60th most requested skill
same proportion of roles as start of 2000 and june of 2001 (3%) peaked at 4.2% may 2000
aprox same number of roles as mid 1999 and late 2001 ( ~ 200 ) peaked about may 2001 at 650
http://www.jobstats.co.uk/jobstats.d/Details.d/Trends.d/SKILL/PERL.d/index.html
I get a jobs.perl.org feed and I have noticed that the UK job market is strong. Now if only I could convince the silly British government to change its employment laws.
And you're not kidding about the Java market there. My brother is a British and a relatively new Java programmer, but he's making a nice paycheck in London right now. Silly me, specializing in Perl instead of Java.
