Which cities are the most expensive for expats?

You may think a pair of jeans costs a lot in London - but try buying a pair in Luanda, where they cost an average of £162. It's just one reason why the Angolan capital has been rated the most expensive in the world for expatriates.

Consultancy firm Mercer has surveyed the cost of living across the world from the point of view of a non-national, based on factors such as housing, transport, food, clothing, household goods and entertainment.

Nearly three-quarters of multinational organisations are expecting the number of staff they send abroad long-term to stay the same or increase over the next two years; and many use Mercer's survey as a way of working out pay rates for these staff.

The price of imported goods makes a big difference to the cost of living for expatriates, as does the ability to find decent accommodation - which is why Luanda tops the list for the second year in a row.

A two-bedroom flat of 'international standard' costs an eye-watering £4,442 a month here, more even than London's £3,200 or Hong Kong's £4,295.

Hong Kong is the second-most expensive city in the list, with Zurich, Singapore and Geneva rounding out the top five.

London is the only British city to feature in the top 20, at number 12 on the list. Glasgow remains steady at 109; Birmingham rose in the ranking to 80th most expensive and Aberdeen to 82nd, while Belfast dropped to 127th.

"UK cities have either increased or remained stable in the ranking, with the exception of Belfast," says Kate Fitzpatrick, a senior international mobility consultant at Mercer.

"While the pound has weakened 8% against the US dollar over the last 12 months, something that would usually push cities down in the ranking, a number of other currencies including the Euro have dropped even more, pushing UK cities up."

Other factors at work include an increase in the price of goods and services in Birmingham and Aberdeen, with similar increases in Glasgow offset by a fall in housing costs. Cheaper housing, meanwhile, has caused Belfast to fall seven places.

"In addition, London remains high because of the continued increase in rental accommodation costs which has offset the drop in currency," says Fitzpatrick.

Average rents across the UK rose by 4% last year, according to a recent report, but by 11% in London. Analysts expect London rental prices to rise by as much as 19.5% over the next five years - meaning the city is likely to keep its place on the Mercer list. Maybe it's time to move somewhere that's apparently cheaper, at 17th on the list: Victoria, in the Seychelles...

Mercer Cost of Living Survey – Worldwide Rankings 2015

1 Luanda, Angola
2 Hong Kong
3 Zurich, Switzerland
4 Singapore, Singapore
5 Geneva, Switzerland
6 Shanghai, China
7 Beijing, China
8 Seoul, South Korea
9 Bern, Switzerland
10 N'Djamena, Chad
11 Tokyo, Japan
12 London, United Kingdom
13 Kinshasa, Democratic Republic of Congo
14 Shenzhen, China
15 Guangzhou, China
16 New York City, United States
17 Victoria, Seychelles
18 Tel Aviv, Israel
19 Buenos Aires, Argentina
20 Lagos, Nigeria