Budget retailer Wilko has entered administration after failing to secure a rescue deal, putting around 12,000 jobs in jeopardy.The chain, which runs more than 400 stores across the UK, told staff on Thursday that it has hired administrators from PwC to oversee the process.Mark Jackson, chief executive officer of Wilko, said the firm had “a significant level of interest” but was “left with no choice but to take this unfortunate action” after being unable to close a deal within time.