Public affairs agency trade body APPC has joined forces with the Trades Union Congress and transparency pressure group Unlock Democracy to call for changes to the lobbying bill.
The trio claim that the Government’s planned statutory lobbying register would result in less than one per cent of lobbying activity being registered.
They have launched a petition and a website under the banner "1% is not enough".
The move comes a week before the bill is first debated by the House of Lords, where it is expected to meet with greater resistance than it did in its journey through the Commons.
The petition calls on the Government to amend its proposals to ensure 100 per cent of professional lobbyists are part of a statutory registration regime in the UK.