Using Emacs ERC behind a HTTP proxy

proxy.el

;; Connect to ERC using a HTTP proxy : ( 
;; *******************************************

(defvar http-proxy-host 
  "www-cache.reith.bbc.co.uk")
  
(defvar http-proxy-port 80)

;; Proxy handler 
;; *******************************************

(defun open-http-proxy-stream
 (name buffer host service &rest parameters)
 (let ((tmp-process
   (apply 'open-network-stream name buffer
           http-proxy-host http-proxy-port parameters)))
 (process-send-string name
   (format "CONNECT %s:%d HTTP/1.1\n\n" host service))
 tmp-process))
 
;; Tell ERC to use our custom handler to connect through a proxy
;; *******************************************

(setq erc-server-connect-function
  'open-http-proxy-stream)
  
;; M-x erc as normal and you're good to go