Why do illegal immigrants so desperate to flee persecution bypass Germany and France in order to come here?
The answer is in your question, they are illegal immigrants. Asylum Seekers, according to international conventions and treaty, must claim political asylum in the first safe haven that the come to. Not to do so, is to forgo the protection of any and all conventions on political asylum and to forgo all rights under those conventions and agreements. Anybody that arrives in the UK, except by direct flight or ship from their homeland are not, by international and legal definition, asylum seekers, they are illegal immigrants. Why do they do it? Because: You don’t have to integrate or learn the language, You get a house ahead of the local population, You get money above and beyond what you need to survive, You don’t get food vouchers, or clothes vouchers, but real money, You can politically agitate against your homeland and the UK, You are safe from repatriation no matter what you do – including murder and rape. Makes sense really.