Dividends - Summary of Dividends Paid (Parenthetical) (Detail) - 5.5% Preference shares [member] - £ / shares |
12 Months Ended | ||
|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2019 |
|
| Disclosure of dividends [line items] | |||
| Per cent dividend | 5.50% | 5.50% | 5.50% |
| Preference shares | 50,000 | 50,000 | 50,000 |
| Par value | £ 1 | £ 1 | £ 1 |