Recent surveys by Gartner and Accenture speak of the phenomenal growth of open source in the enterprise. We have witnessed this in the PHP world as well:

• The number of organisations migrating their legacy technologies to PHP
• Growing number of enterprise-ready packages/platforms based on PHP (Magento, SugarCRM, etc)
• The strength of the PHP community
• The number of companies recruiting for PHP developers in the UK.

There is no doubt that PHP has become a very powerful and mature development platform, which companies are embracing for large-scale, mission-critical applications.