MPs should not accept any murky answers from Thames chair about its potential sale

Urrah, Sir Adrian Montague, the chair of Thames Water, is scheduled to make another of his rare public appearances.

- Nils Pratley

Tomorrow he will be at the environment select committee, where 18 months ago he gave a strong signal that the company's financial crisis was even worse than feared.

The shareholders, in their standoff with the regulator over bills, wanted to know the business was "investable," said Montague. Three months later those investors decided it wasn't and refused to put in another penny. That resulted in the current refinancing contest in which the US private equity group KKR was chosen as the preferred bidder in late March.

The MPs should press Montague on three points. First, why KKR? It is a big, grown-up investor in infrastructure projects around the world so qualifies as credible from a financial perspective, even if half the job at Thames is repairing a balance sheet wrecked by another set of financiers (Macquarie).