Carefully whisk the loose tea and 1.5 litres boiling water together in a large heatproof bowl. Leave to steep for 8 mins. Meanwhile, set a sieve over a large jug and line with muslin.

After 8 mins, carefully pour the tea through the lined sieve and squeeze to extract all the flavour (it will be hot, so be careful). Whisk in the condensed and evaporated milks, then chill for 1 hr. Fill a serving jug with ice, pour in the tea, then serve in tall glasses over ice with reusable straws.