This excerpt taken from the NDAQ 8-K filed Nov 20, 2006.
14. Compulsory acquisition, cancellation of listing and re-registration
If the Ordinary Offer becomes or is declared unconditional in all respects and NAL receives sufficient acceptances under the Ordinary Offer, it will be NALs intention:
Such cancellation of LSEs listing and admission to trading will take effect no earlier than the expiry of 20 business days after the Final Offers become or are declared unconditional in all respects. De-listing would significantly reduce the liquidity and marketability of any LSE Shares not assented to the Final Offers.