LONDON, Feb 13 (Reuters) - Britons may have to brave a shortage of some lines of tea, one of the nation's favourite drinks, after the supermarket industry warned of a risk to supply from shipping disruptions in the Red Sea.

The British Retail Consortium said it had seen "temporary disruption" to some black tea lines, and an industry source said there had been some delays to flavoured lines.

Although the country's two biggest supermarket groups showed ample supply on their websites on Tuesday, companies have warned in general that the length of disruptions to Red Sea shipping will determine whether consumers see empty shelves in Europe.

The warning of delays is the first for a food item, following several from clothing retailers after Iran-aligned Houthi militia attacked ships in and around the Red Sea, slowing trade between Asia and Europe.

Britain, the world's fifth largest tea importer, gets more than half of its imported tea from Kenya and India, making it dependent on the Red Sea route.

Unprocessed tea is shipped into the UK for processing and packaging, helping to make Britain the 10th largest exporter globally, according to the Institute of Export & International Trade (IEIT).

"There is temporary disruption to some black tea lines, but the impact on consumers will be minimal as retailers are not expecting significant challenges," said Andrew Opie, director of food and sustainability at the British Retail Consortium, which represents the major supermarket groups.

An industry source familiar with UK area manufacturing said that while there were a few delays, they did not expect a big shortage.

IEIT director general Marco Forgione said tea may be "the first of many items caught up in this supply chain crisis".

The alternative shipping route around South Africa's Cape of Good Hope can add 10-14 days to a journey compared to passage via the Red Sea and Suez Canal.

Several major UK clothing retailers, including Next, Pepco Group, Primark and Matalan, have cautioned on the potential impact of disruption to Red Sea shipments. (Reporting by James Davey; Additional reporting by Richa Naidu; Editing by Jan Harvey)