Boris Johnson water debate: Compensate Wales - Wigley
Former Plaid Cymru leader Dafydd Wigley says Wales should be compensated if water supplies are taken from Wales to ease shortages in England.
He entered the debate over who has powers over natural resources after London mayor Boris Johnson supported moving water to drier English areas.
Mr Johnson said rain from Wales and Scotland could help parts of the UK in the south and east.
Lord Wigley said the mayor's comments were "quite a surprise".
Writing in the Daily Telegraph last week, Mr Johnson suggested using "surplus rain from the mountains to irrigate and refresh the breadbasket of the country in the south and east".
Lord Wigley told the BBC's AMPM programme on Wednesday that devolution should be able to stop another Tryweryn - the valley in Gwynedd that was flooded in the 1960s to create a reservoir to supply Liverpool.
The former Plaid leader raised the issue in the Lords but said he had "a non-committal answer".
He said that "this issue will not go away and needs to be sorted out".
"The belief was that the National Assembly would be enough to safeguard Wales from ever seeing another Tryweryn," Lord Wigley said.
"Questions now arise over whether clauses in the 2006 (Government of Wales) Act mean that London ministers have a veto over the National Assembly.
"Local communities in Wales should also be able to veto proposals to flood valleys in Wales which have been earmarked to supply water to drought hit cities in England.
"Wales should be compensated for water taken in such a way."