Simple and inefficient word unjumbler!

jumbled_word_solver.py

import sys
import time
import webbrowser
WORDS_FILE = 'words_alpha.txt'
num_words = sum(1 for line in open(WORDS_FILE))
def permutation(lst):
    if len(lst) == 0:
        return []
    if len(lst) == 1:
        return [lst]
    l = []
    for i in range(len(lst)):
       m = lst[i]
       remLst = lst[:i] + lst[i+1:]
       for p in permutation(remLst):
           l.append([m] + p)
    return l
def solve(word):
    word = word.lower()
    letters = []
    words = []
    for letter in word:
        letters.append(letter)
    print('Permuting word, this may take a while...')
    for peword in list(permutation(letters)):
        pword = ''
        for letter in peword:
            pword += letter
        words.append(pword)
    print('\nDone Permuting. Found '+str(len(words))+' possible combinations.')
    if len(word) >= 7:
        time.sleep(3)
    elif len(word) >= 2:
        time.sleep(1)
    print('Scanning '+str(num_words)+' words from dataset...')
    valid_words = []
    f = open(WORDS_FILE)
    counter = 0
    for i in range(num_words):
        valid_word = f.readline()[:-1]
        if valid_word[0] in word:
            if len(valid_word) == len(word):
                print('Found word with same length. Verifying word: '+valid_word)
                if valid_word in words:
                    valid_words.append(valid_word)
                    counter +=1
                    webbrowser.open('https://google.com/search?original='+word+'&q='+valid_word)
                    print('Verification successful! Adding to list.')
                else:
                    print('Word failed verification, continuing...')
    f.close()
    print('\nFound '+str(len(valid_words))+' words from dataset\n')
    counter = 0
    for word in valid_words:
        counter +=1
        print(str(counter)+': '+word)
while 1:
    word = input('Jumbled word: ')
    solve(word)

A new and exciting version is here: https://gist.github.com/bugbrekr/891a0a58ef05b211a8027c0c2c582a5a