Not again. Never mind, I am here to explain. (Hopefully V4 is coming soon, and please, get this question to the first page!)

BEng and MEng are both undergraduate degree, meaning your first degree after your Pre-U.
The difference between BEng and MEng, other than the year it spends, is the possibility of getting accredited.
Today, to become a professional engineer (bearing the title Ir. or CEng or PEng depending on where you get accredited), you must study for 4 years during your tertiary studies. If you do not possess a 4-year degree, you will have to continue further study, or sit for their exams, so that you are qualified to work towards of becoming a professional engineer.

A little bit of history. BEng is always a 3-year course in UK education, as compared to 4 years in other countries. This is because UK education is rather concentrated, studying the core elements and do not waste time on the unrelated contents. Due to this nature, they are able to concentrate the course into 3 years. But the problem comes when everyone else in the world says, they will only accredit those degrees which are only of 4 years in length. To counter that, UK decides to come up with a 4-year MEng, instead of elongating their BEng into 4 years. The extra year, essentially teaches you more stuff, and also prepares you better to join the industry.

You may now wonder then, is our MEng the same as those Aus BEng? The answer is, NO, except when it comes to getting accreditation. A quick proof would be comparing the course structure side by side. You will find that, while Aus students still study Physics and Chemistry in their first semester/year, UK is already delivering the core contents of the respective course. For instance, for Mechanical, instead of just studying Physics, you already start off with Thermofluids and Solid Mechanics. Why? Because A-Level delivers more contents than SAM/AUSMAT/HSC, so they can just start with more advanced topics already.

Regarding further study, you may be surprised that, even a 3-year BEng could earn you a PhD seat in a UK university. This holds true within UK but not so true to the rest of world. Often the time, a lot of universities will clarify that a 4-year degree is required before one can start his/her Master/PhD, so a mere 3-year BEng will simply be insufficient to apply successfully. Harvard, for instance, actually states that one needs to do 6 years before they can start a PhD there. The specification of 6-years, means that even if you are a Master, you do not yet have the qualification to do it.

As for why you need accreditation, it really depends. If you are from Civil, go and get your MEng and practise in getting the Ir. title. It's vital for the Civil sector. As for the other main streams (Mech, Chem, EE), it is not that important in Malaysia. This is because, Boards of Engineers Malaysia (BEM) has yet to be so strict on the accreditation stuff that only accredited engineers can do the jobs. Intel hires BEng, for example. And with such phenomena happening, it makes the BEng a great course to sell, as it still promises jobs (as long as you get a good class) while it comes cheaper and faster than others. The drawback is the not-so-important (for now) accreditation thingy in Malaysia. Oh, one more thing, it is not uncommon to do the route of BEng, followed by a more specialised MSc (Master of Science, a postgraduate degree in UK). For instance, a BEng in Mechanical Engineering and later a MSc in Aerodynamics.

Of course, I may be biased, although I try to be as neutral as possible by supplying evidence for my claim.

Pin this. If we can't pin it into the V3 one, do it on the V4!!