I hold a masters degree in electrical engineering, and have lately (last 20 yrs) been specializing in satellite communications. I got my bachelors in 1969, worked for a while, then went back and got a masters (in 1987) - when i noted that many new job applicants (right out of school) already had masters degrees. Over the years, i have worked in 14 countries doing engineering. I have never changed jobs and taken a cut in pay. A few times it was a 'lateral' (same new pay as old), most of the time i got a substantial raise in pay. I joined the US Federal government right out of my bachelor's uni, and stayed there about 15 yrs. I took an overseas 'tour' with them, and stayed in the near east for over 2 years. I came back to the states with enough dosh to buy a house. This put me 'ahead of the power curve' enough that i was able to sock extra money into stocks and other investments.
I stayed with the government for about 15 yrs, I finally came to my senses, and circulated my resume' (CV) "around the beltway", as they say, and the high bidder offered a 37.5% increase in pay. At the same time, i had talked to the "retirement affairs" section of my employer, and found that with their retirement "plan" - i would be getting $1100 in th year 2000 to retire on. At that time, in the D.C. area, flats were renting (a 2 bedroom one in a part of town where you could go outside at night - without being attacked), for about $1600 to $2000 a month. So their "pension" wouldn't even pay my rent.
I left the government, ending up with a much more relaxed work environment, and higher pay. Over the years, i changed jobs a number of times, even teaching at uni a couple of times [which i am qualified to do with my masters degree]. Now, i clear about $2050 a month from Social Security [our national retirement system - i qualified with enough months of 'outside government employment' to get that], plus i get another $500 (approx) from two private pensions i picked up in connection with my private employment, after i left the government. I also have some outside investments, which i made with the 'excess' salary i picked up when i left the government. I haven't had to touch that yet.
I concur that people will try to exploit you if you're an engineer. It is worthwhile to keep your eye on the job market, and circulate your CV periodically, just to see what salaries in your specialty are running. An advanced degree is a plus in my estimation. Also, you have to be willing to relocate from time to time, as new programs come on line. Living overseas is enjoyable (i think), and opens up all kinds of new possibilities. I also agree that engineering pay in the Uk is quite low. Couple this with the very high taxes you have, and i'd not consider taking a job there. Generally, you do best, taking a job where nobody else wants to go. London, Rome, Paris, Frankfurt, D.C. - all are high cost/lower pay locations. You do best taking a job where nobody else wants to go, and they have to 'bribe' people to live there. When you are young, and don't mind living where you sleep on a cot & eat cold food a bit of the time, you can sock away the money. My first overseas job was described (accurately - by the US State dept.) as an "isolated, extreme hardship post". When i finished 2 years there, i had over $30,000 in the bank (starting with nothing). I also had enjoyed 2 skiing trips (2 weeks duration each) at US Government expense - you gotta do something on your R&R!!
Over the years, i have worked in (as far as i can recall) every US state [except perhaps Arkansas]. I loved Alaska, but then i wasn't there in winter. Hawaii was nice too, but kinda crowded and touristy. Expensive too - nearly as bad as the Uk. I would recommend engineering, but keep your skill set current, don't be afraid to move (or change jobs), and keep an eye on your pension money. I would NOT recommend letting your employer handle your money or run your pension plan. Don't let them 'fund' your retirement with company stock - it may well turn out to be worthless. If you want stock in your own company - buy it from an outside broker - as an IRA for example. Nearly all employers will pay your tuition for graduate school. They get a tax deduction on what they pay - so everyone wins. Foreign languages can be handy, but given the choice of studying them or engineering - i'd recommend engineering. You can always hire a translator (pretty cheaply). Its only in intelligence work that having in-house translation capability is really worthwhile. Cheers.