Teaser 2890: Squares on cubes

From The Sunday Times, 11th February 2018 [link]

Liam has a set of ten wooden cubes; each has a different number (from 1 to 10) painted on one face (the other five faces are blank). He has arranged them in a rectangular block with all numbers upright and facing outwards. Each vertical side of the block shows some numbers which can be read as a number that is a perfect square. No two square numbers have the same number of digits.

Which square number must be present?