English is the Lingua Franca- good or bad for Britain?

On the surface of it, it is very convenient for the British (and other English-speaking nations), as they can travel much of the world and be understood, as English is the lingua franca. But this also poses problems for the British, an issue highlighted as a consequence of recent government efforts to promote the study of languages in British schools. It is all well and good that the government is encouraging primary and secondary schools to teach French, Spanish and Mandarin. But unless these were the exclusive subjects taught at school, or multiple subjects were taught in these languages, pupils are not going to become fluent. So by the time pupils finish school they will know only a few token phrases- nowhere near enough to get by when travelling. The advantage to countries that include non-native English speakers is that outside of lessons, people are likely to listen to English-speaking music and watch English-speaking films. Moreover, when they travel overseas, due to English being the lingua franca, two people from different nationalities are likely to communicate in English- despite it not being their native language. Meanwhile, a vast majority of Britons are not regularly exposed to foreign languages to this extent, and therefore do not have the shared incentive to learn these languages. As mentioned at the beginning, most Britons are nevertheless still in an advantageous position by being native English speakers. But then again, opportunities are hindered by speaking only one language fluently. For example, consider the allowances that are made in the EU to better ensure a higher proportion of British employees within the EU, an allowance not taken advantage of by many Britons due to their inability to speak a language besides English fluently. There is another drawback to speaking the lingua franca. It means that, whilst a smaller proportion of Britons can take advantage of opportunities elsewhere in the non-English speaking world in terms of work, particularly in other EU countries; meanwhile the far greater proportion of those who are not native English-speakers, but nevertheless have it as a second language, are able to work easily in Anglosphere countries- like Britain. With Britain weathering the economic relatively well, particularly when compared with elsewhere in Europe, many workers from the EU already have a great incentive to use their right as an EU/EEA citizen to work in the UK. Meanwhile the balance of workers entering Britain to work would already be relatively high, precisely because its language is indeed the lingua franca. Thus, as the proportion of EU/EEA workers migrating to Britain is likely to be high already as a relatively economically stable country, the speaking of English in the UK is bound to tip this balance even more, adding further challenges to a country already dealing with an increasing and dense population. Such problems include the availability of housing (when it is not plentiful enough to house a larger population, it drives prices higher, as is currently the case despite the recession), utilities (water, electric and gas resources are spread more thinly amongst a larger population) and public services, such as benefits, healthcare and education (when the government is already dealing with a deficit regarding public spending).