Improving the functioning of the Stability and Growth Pact (SGP) is back on the agenda, especially as the decline in public investment resulting from fiscal adjustment processes implemented according to the current Pact rules is seen as a brake on future economic growth. When discussions about a Pact revision in 2005 were under way, several major authors (for instance: Blanchard and Giavazzi in CEPR February 2004) suggested reverting to a golden rule under which the deficit would exclude investment expenditure, net of amortization. The Pact was revised in 2005 but this proposal was not adopted. This paper presents a new attempt to integrate a proper accounting of investment into the Pact by modifying the formula of the MTO (Medium Term Objective for the budget balance), without losing the other dimensions of the present formula: the partial provisioning of the so-called cost of ageing and the accelerated debt reduction for highly indebted countries. In this way, the public investment programme becomes a centrepiece of the structural policy of a government and not the first instrument of a cyclical policy.