Broadcasting groups Sky and Liberty Global are understood to be interested in making a bids for a GBP 4.5 billion controlling stake in the Formula One (F1) global motor racing series, reports The Sunday Times. The F1 stake in question is currently owned by private equity company CVC. Unnamed city sources indicate that Liberty and Sky have held informal talks with CVC about a deal. The report follows news that RSE Ventures and Qatar Sports Investments had joined forces for a F1 bid.