The change in date for the season-opening Australian Grand Prix forced McLaren staff to sacrifice time from their Chistmas breaks to get the team's 2016 car back on schedule.
Originally slated to start on April 3, modifications to the 2016 calendar last September brought the Australian Grand Prix forward to March 20. Teams had been concerned about the impact of a later start on the condensed calendar, with a street race in Azerbaijan bringing the numbers up to a record 21 for the year.
McLaren endured its worst season since 1980 last year after struggling with the returning Honda's uncompetitive and unreliable power unit. It hopes to return to competitiveness this season with the MP4-31 and with gains expected from Honda.
However, the altered calendar hampered McLaren's development schedule and operations director Simon Roberts says it meant staff in Woking had to work during their holidays in December.
"Our entire build programme wasn't lined up for that!" McLaren's operations director Simon Roberts told the team's website. "So we knew we had a problem to solve. In terms of our design and engineering capacity, it's a relatively straightforward re-planning exercise - there's less time to get the work done, so everyone works a bit harder.
"But the build schedule is on a critical path -- it needs to pass all the FIA safety tests and be ready for the first test, which was also brought forward. In that situation, you can't just re-plan, you need to do something different."
Roberts says the hard work from those who came in over Christmas paid dividends and has put the MP4-31's development back on schedule.
"In simple terms, we put about eight shifts of work back into the programme over a five-day period - a fantastic effort. In total, there were about 110 people involved and we looked after our Christmas workers with a competitive package.
"We had a really good response, and people seemed to enjoy it too -- it was a bit weird, not having all the time off, but there was a good spirit in the place. Everyone knew why they were doing it, and it really cleared the decks. Most pleasingly, it meant that, once we came back in the New Year, we were back on schedule - and it felt like the programme had always been phased that way. It was an incredible effort."
McLaren has confirmed it will launch its new car on February 21, the day before testing begins in Barcelona. Sauber also fell victim to the late change in date for the Australian Grand Prix and will not debut its 2016 car until the second test the following week.