Former Sheffield Hallam MP Richard Allan explains why over on his blog:

The process of deciding law in the European Parliament is much more complex than in Westminster. In Westminster virtually every word of our laws is drafted by the Government with the odd amendment passed in the House of Lords where there is no Government majority. The scrutiny process can throw up errors and occasionally creates such controversy that a proposal is delayed or abandoned. But it does not generally offer individual MPs the opportunity to make substantial changes to the law.

In the European Parliament, individual MEPs with key places on legislative committees have real power in the drafting of laws. They are then able to work with their political groups to swing support behind their proposals. The key dynamic is usually between the three big political groups – the socialists, the centre-right and the liberals – as two of these coming together can command a Parliamentary majority.

Yet, in the European elections on Thursday, the UK is likely to end up with fewer MEPs in these three main groups and therefore will potentially have less direct influence over legislation. The Conservatives have made their case for pulling out of the main centre-right group and claim they can still work effectively with their old allies from a new grouping.

That last point about the Tories is covered in more detail at Jonathan Fryer’s blog today:

It is often said that one can judge a man by the company he keeps. So no wonder Tory grandees such as Chris Patten and Leon Brittan are appalled that the Conservative Party leader David Cameron is making new alliances with some of the most unpleasant parties in mainstream European politics, as a consequence of pulling out of the centre-right EPP grouping in the European Parliament. These new friends include Poland’s Law and Justice Party, fiefdom of the Terrible Twins, Lech and Jaroslaw Kaczynski, and self proclaimed defender of traditional Catholic values. Lech is now Poland’s president, but while Mayor of Warsaw, he banned Gay Pride marches. His brother Jaroslaw declared that the affirmation of homosexuality would lead to the downfall of civilization. So much for the Tories’ newly vaunted inclusiveness.

Latvia’s For Fatherland and Freedom Party, another of the right-wing parties with which the British Conservatives are making an alliance, is in many ways more worrying, with its xenophobic hyper-nationalism. Others reportedly being wooed by team Cameron include intolerant groups in the Czech Republic. The fact that Cameron prefers to mix with people like these, rather than his earstwhile partners Angela Merkel and Nicolas Sarkozy, highlights not only the degree of his party’s current euroscepticsm, but also his recklessness in contemplating marginalising Britain from central decision-making within the European Union. No surprise, then, that several of the outgoing Conservative MEPs have branded the whole Cameron policy of Tory realignment in Europe as bonkers.

And since this entire blog post for LDV is turning into a complete clipfest from around the other blogs, here’s a final few words from Alex Wilcock (do put aside 40 minutes and go and read the whole post as well, though!):

In London, polls suggest that the Greens will hold their single MEP, but have no chance of getting a second. Liberal Democrat Jonathan Fryer, though, was only 0.06% of Londoners’ votes short of becoming the Lib Dems’ second London MEP last time. So, a Liberal Democrat vote should be able to give him just that tiny bit extra he needs to be elected. Besides, if you really want to make the BNP miserable after the election, can you think of a better way to do it than making sure the MEP that takes the place they were hoping for is from the most internationalist party, the most socially Liberal party, and, in London, an out gay man?