**Masa Musim Panas British** (bahasa Inggeris: *British Summer Time*code: en is deprecated  [BST]) atau **Waktu Musim Panas Greenwich** ([*Greenwich Daylight Savings Time*] Error: {{Lang}}: teks mempunyai penanda italik (bantuan) [GDT]) ialah waktu sivil sewaktu bulan-bulan musim panas di United Kingdom apabila waktu jam dimajukan berbanding Waktu Min Greenwich (GMT) sebanyak satu jam. Ia diasaskan oleh *Summer Time Act* pada 1916, telah dipinda mengikut akta-akta berikutnya dan kini ditakrifkan oleh *Summer Time Order* pada 2002 yang telah menjelaskannya sebagai 

> ...waktu bermula pada pukul satu, waktu min Greenwich, pada pagi hari Ahad terakhir pada bulan Mac dan berakhir pada pukul satu, waktu min Greenwich, pada pagi hari Ahad terakhir pada bulan Oktober.—The Summer Time Order 2002

Masa musim panas berganda
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Sewaktu Perang Dunia II, Britain mengekalkan kemajuan jam pada GMT di permulaan musim sejuk pada 1940 dan berlanjut memajukan jam dengan satu jam tambahan hingga Julai 1945. Sewaktu musim panas ini Britain oleh itu memajukan 2 jam hadapan GMT dan mengoperasikan pada *British Double Summer Time*. Jam ini telah dikembalikan ke GMT pada akhirnya musim panas 1945. Pada 1947 jam-jam telah dimajukan sebanyak satu jam dua kali sewaktu musim bunga dan diletakkan dua kali sewaktu musim gugur supaya Britain berada di BDST sewaktu puncak musim panas.

Bantahan
--------

Perdebatan occasional meletus ke atas validity of BST, oleh kerana Britain's latitudinal length. Pada 2004, suatu penyumbangan menarik telah dilakukan oleh AP Inggeris Nigel Beard, yang menjadualkan suatu Bil Ahli Swasta di Dewan Rakyat mencadangkan bahawa England dan Wales seharusnya menentukan waktu mereka berdikari dari Skotland dan Ireland Utara. Jika ia telah diluluskan ke dalam undang-undang, bil ini akan secara berpotensi telah melihat United Kingdom dengan dua zon waktu berlainan pada waktu pertama sejak pembubalan Waktu Min Dublin (25 minit mundur Greenwich) on 23 August 1916.

Sestengah gerakan akar-rumput bermuncul untuk pembubalan BST secara keseluruhannya, menggemarkan GMT sepanjang tahun. Mereka biasanya menyatakan kekurangan keuntungan praktikal dari pengubahan waktu, selain itu mooting bahawa pengubahan jam sekolah dan/atau bisnes akan mengesankan perubahan yang sama tanpa gangguan piawai saintifik.

Waktu Musim Panas tunggal/berganda
----------------------------------

Safety campaigners, including the Royal Society for the Prevention of Accidents (RoSPA), have made recommendations that British Summer Time be maintained during the winter months, and that a "double summertime" be applied to the current British Summer Time period, putting the UK one hour ahead of GMT during winter, and two hours ahead during summer. This proposal is referred to as "Single/Double Summer Time" (SDST), and would effectively mean the UK adopting the same time zone as central European countries such as France, Germany, and Spain (Central European Time and Central European Summer Time).

RoSPA suggest this would reduce the number of accidents over this period as a result of the lighter evenings, as was demonstrated when the *British Standard Time* scheme was trialled between 27 October 1968 and 31 October 1971, when Britain remained on GMT+1 all year. Analysis of accident data during the experiment indicated that while there had been an increase in casualties in the morning, there had been a substantially greater decrease in casualties in the evening, with a total of around 2,500 fewer people killed and seriously injured during the first two winters of the experiment. RoSPA have called for the two year trial to be repeated with modern evaluation methods. The proposal is opposed by farmers and other outdoor workers, and many residents of Scotland and Northern Ireland, as it would mean that, in northern Britain and Northern Ireland, the winter sunrise would not occur until 10:00 or even later.

In 2005, Lord Tanlaw introduced the Lighter Evenings (Experiment) Bill into the House of Lords, which would advance winter and summer time by one hour for a three-year trial period at the discretion of "devolved bodies", allowing Scotland and Northern Ireland the option not to take part. The proposal was rejected by the government. The bill received its second reading on 24 March 2006; however, it did not pass into law.  The Local Government Association has also called for such a trial.

Lihat juga
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* Waktu Musim Panas Eropah Barat
* Waktu musim panas
* Waktu buka lampu

Rujukan
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1. ↑  *Statutory Instrument 2002 No. 262 The Summer Time Order 2002*, HMSO, 20 Februari 2002, ISBN 0110393317
2. ↑  *Lighter nights would keep youngsters fitter and safer, say doctors...*, Western Mail, 27 Jun 2005, diarkibkan daripada yang asal pada 2019-12-15, dicapai pada 2009-10-01
3. ↑  "Press Release October 22, 2008 IT'S TIME FOR A CHANGE TO SAVE LIVES AND REDUCE INJURIES". RoSPA Press Office. Diarkibkan daripada yang asal pada 2009-03-17. Dicapai pada 2009-10-01."British Summer Time (BST)". NMM - National Maritime Museum.
4. ↑
5. ↑  "Lighter Evenings (Experiment) Bill".
6. ↑  "Clock change 'would save lives'". BBC News. 2006-10-28.

Pautan luar
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* Bank holidays and British Summer Time from the UK Government website Directgov.