He declared: "Let's together resolve today, all of us, to confront our opponents with the truth. Let's all fight them with the facts." We have subjected his claims to a factual audit.
Claim: Mr Lang cited the case of Olivier Cadic, a Frenchman who "moved his entire printing company from Paris to Kent just to get away from the Social Chapter".
Fact: Mr Cadic's company, Info-Elec, is moving 15 of his 25 staff from France to Ashford in Kent, as reported exclusively in The Independent last month. But the move is nothing to do with the Social Chapter. He made it clear it was because wages and payroll taxes are lower in Britain.
Claim: "Britain is exporting more goods and services abroad today than at any time in our entire history."
Fact: Assuming steady growth, it would be surprising if this were not the case. Britain's share of world trade is its lowest ever - which is also unsurprising, given the expansion of the developing countries.
Claim: "Unemployment in this country has fallen further and faster and for longer under us than at any time in the last 50 years."
Fact: This partly reflects the fact that it had further to fall after exceeding 3m in the early 1980s, the highest for 50 years.
Claim: "We have more of our people in work in this country than in any other major country in Europe."
Fact: People in Britain start work younger and retire later than their Continental counterparts. And for historical reasons more women tend to have paid work in Britain than in other European countries.
Claim: "Britain's growth in productivity has taken us from the bottom of the G7 group of nations to the top."
Fact: There has been a dramatic improvement in productivity in manufacturing, although the rankings depend on choice of dates. The Department of Trade and Industry cited OECD figures for 1980-95, but said Britain was second from bottom in 1973-79. The figures do not apply to service industries, where improvements have been less impressive.
Claim: "More foreign companies have chosen to come here to invest in the past 10 years than to any other country in Europe - over pounds 100bn-worth."
Fact: Inward investment per head of population is four times higher in Belgium. Labour points out that Britain also has the highest "outward investment", capital exports, of any country in the EU.Reuse content