21 February 2011 Last updated at 07:52 ET

Who, what, why: What difference would double summertime make to you?

A proposal to move the nation's clocks forward by one hour to so-called "double summertime" will be published this week. So what difference would it make to sunrise and sunset in towns and cities across the UK?

Prime Minister David Cameron has said any plans to give the UK brighter and longer evenings will only become a reality if it's clear that the country is behind it.

But support for the move, which would make mornings darker, may depend upon where people are.

If you live in London, then sunset would be at 2222 on 21 June, which is the longest day of the year. But in the winter solstice, on 21 December, it would not be fully light until sunrise at 0904.

It would be a very different experience if you lived in Thurso in the Scottish Highlands, where under "double summertime", the sun would not set until 2327 in mid-summer but it would not rise until 1003 in mid-winter, a long time after children had started school lessons.

So how would it affect you? Seven cities are mapped above, and below, there are 10 more cities around the UK with the new sunrise and sunset times on the longest and shortest days of the year.

How double summertime would affect you
Place	21 June 2011	21 Dec 2011
Source: HM Nautical Almanac Office
Bangor, Gwynedd	Sunrise 0549 Sunset 2248	Sunrise 0929 Sunset 1700
Birmingham	Sunrise 0544 Sunset 2234	Sunrise 0916 Sunset 1655
Bristol	Sunrise 0553 Sunset 2231	Sunrise 0913 Sunset 1703
Glasgow	Sunrise 0531 Sunset 2307	Sunrise 0946 Sunset 1644
Hull	Sunrise 0530 Sunset 2236	Sunrise 0917 Sunset 1642
Leicester	Sunrise 0540 Sunset 2232	Sunrise 0913 Sunset 1651
Londonderry	Sunrise 0550 Sunset 2312	Sunrise 0952 Sunset 1702
Newcastle-upon-Tyne	Sunrise 0527 Sunset 2249	Sunrise 0929 Sunset 1639
Norwich	Sunrise 0531 Sunset 2222	Sunrise 0904 Sunset 1642
Portsmouth	Sunrise 0551 Sunset 2221	Sunrise 0904 Sunset 1701