Commitments and Contingencies Contingencies (Details) £ in Millions	12 Months Ended
Apr. 30, 2020 GBP (£)
Loss Contingencies [Line Items]
Loss Contingency, Amount Sought by Counterparty	£ 49
Loss Contingency, Amount Withheld by Counterparty	£ 34

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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