The so-called "EdStone" stone tablet bearing Ed Miliband's 2015 general election pledges has helped land Labour a £20,000 fine from the electoral spending watchdog.
Labour omitted two payments totalling £7,614 relating to the eight foot block of stone from its election campaign spending return, a breach of the rules which sparked an Electoral Commission investigation.
The party was then ordered to review all of its election expenditure and the commission's subsequent analysis has concluded it missed 74 payments totalling £123,748, as well as 33 separate invoices totalling £34,392 from its spending return.
Labour treasurer Iain McNicol was found to have committed two offences under the Political Parties, Elections and Referendums Act 2000 (PPERA) and the party has now been fined £20,000.
It is the largest fine the Electoral Commission has imposed since beginning operations in 2001.
The commission's investigation into Labour's 2015 general election campaign spending return was opened on January 22 following allegations that it may have been incomplete.
The watchdog said: "Initial inquiries aimed to determine why two payments totalling £7,614, relating to spending incurred on a stone tablet - referred to in the media as the 'EdStone' - were missing from the party's campaign spending return.
"It was established that these payments were missing from the party's return and the commission launched an investigation."
Labour then carried out an internal review of its expenditure which found additional missing items as well as the omitted spending relating to the widely-mocked stone tablet.
The commission then identified further missing payments, including costs associated with the Labour Express and Labour Students tours, and items of spending by an individual candidate which had been allocated to central party spending but not included in the return.
In addition 33 invoices with a value greater than £200 were missing from the return, totalling £34,392.
The commission called in February for an increase in the maximum £20,000 penalty available to it for a single offence to an amount more in proportion with the spending and donations handled by large campaigners.
Its director of party and election finance, Bob Posner, said: "The Labour Party is a well-established, experienced party.
"Rules on reporting campaign spending have been in place for over 15 years and it is vital that the larger parties comply with these rules and report their finances accurately if voters are to have confidence in the system."
A Labour Party spokeswoman said: "Labour has co-operated fully with the Electoral Commission during its investigation into general election 2015 campaign spending by political parties.
"The commission's investigation found that internal procedural errors led to a relatively small number of items of expenditure not being declared properly.
"The party regrets these administrative errors.
"However, these amounted to just over 1% of our total spending of over £12 million during this election.
"We accept the findings of the report and have already tightened our internal recording procedures to address the commission's concerns."