The great British Fish 'n' Chips culinary couple show no signs of breaking up after 150 years together.
Jewish immigrants introduced fried fish to London as early as the 17th century. One of the earliest noted record of fried fish is to be found in Charles Dickens' Oliver Twist, published in 1837, where he referred to a "fried fish warehouse."
Both Lancashire and London lay claim to the invention of the classic takeaway dish.
Southerners claim the first fish and chip shop was set up by a Jewish immigrant, Joseph Malin, in 1860 in East London. In the north of England, where French "Pommes Frites" soared in popularity during the 18th century, locals claim the first shop opened in Mossely, Lancashire in 1863.
"The discussion as to whether it originated in the south or the north merely shows the affection the whole country has for it," explained Westminster MP Lindsay Hoyle as part of Britain's national Fish and Chips Week.
Although some critics describe it as culinary hara-kiri, the UK now boasts around 11,500 fish and chip shops, stretching from John o' Groats to Land's End. All agree that the dish is to Britain what pizza is to Italy.
Despite the advent of other fast food rivals, such as doner kebabs, burgers, pizza and curry, fish and chips remains the number one, with over 300 million portions sold in 2009.
A national institution
"The dish is a national institution," says Ahmet Ziyaeddin, 40, who along with his brother Ali runs London's oldest fish and chips shop - Rock & Sole Plaice.
The shop, which has been in the Ziyaeddin family for two generations and was first founded in 1871, is popular with celebrities such as Anthony Hopkins and Lily Allen.
While more up-market shops, such as Birmingham's Great British Eatery, are directed at gourmet cuisine, Ziyaeddin refuses to add any modern dishes to his menu.
"Half our customers are tourists," he explains. "They want the dish in its purest form."
One area where Ziyaeddin and other fish and chips owners have had to compromise is in the area of packaging. To keep prices low, fish and chips were originally served in newspaper. But health and safety regulations have banned the practice since the 1980s.
Further efforts to improve the image of Britain's national dish are taking place on its 150th anniversary with the National Federation of Fish Friers pointing out that fish and chips have 42 per cent less fat than the average doner kebab.
However, with around 1,000 calories per serving, fish and chips could hardly be considered health food.
"Fish and chips is the healthiest of unhealthy foods," says Ziyaeddin with a smile.