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Organisers of the last Korean Grand Prix claim they were given no notice of the return of the race on next year's calendar.

After four years in F1, the Korean GP was dropped in 2014 following poor ticket sales and failed negotiations to lower the sanctioning fee for the event. However, it made a surprise return to the 2015 calendar - published by the FIA on Wednesday - as the fifth round of a 21 race calendar, albeit with a "to be confirmed" note next to it.

Speaking to AFP, one official for the last race in 2013 said: "We were given no prior notice. The FIA just announced it, although we've already conveyed our position about the difficulties of hosting a race next year."

Two theories are doing the rounds to explain the surprise addition. Reuters reports that the race has been added to find a way around next year's engine regulations, which are set to limit the amount of power units available to each car from five to just four.

Drivers face large grid penalties for exceeding their allocation of power units, and meeting the more stringent regulations could prove difficult for some manufacturers next year. Changing the regulations in a straightforward manner would require the unlikely unanimous agreement from all the teams, but there is a provision in the regulations to allow a fifth power unit to be used if there are more than 20 races on the calendar. However, given the race officials' surprise at Korea's proposed return, it remains to be seen whether the race would actually go ahead or if the clause will be triggered even if it does not.

The second theory is that the round has been added to generate support for a street race in Seoul. But with the event scheduled to take place on May 3 next year, it is very unlikely a street race could be prepared in time, especially as officials at the existing circuit in Yeongam have already flagged their concerns about being ready in time.

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